Journal articles on the topic 'Oocytes competence'
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1
Walker, Bailey N., and Fernando H. Biase. "The blueprint of RNA storages relative to oocyte developmental competence in cattle (Bos taurus)." Biology of Reproduction 102, no. 4 (January 26, 2020): 784–94. http://dx.doi.org/10.1093/biolre/ioaa015.
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Abstract From the time oocytes leave quiescence, there are constant microenvironmental influences contributing to development, thus acquiring developmental competence is not a simple, linear phenomenon. During folliculogenesis, oocytes experience many morphological and cytological changes that contribute toward the acquisition of developmental competence, a process defined by an oocyte’s ability to progress through folliculogenesis, be fertilized, undergo cleavage, and develop into an embryo. Many factors, such as ovarian follicle size, cow age, and the morphology of the cumulus–oocyte complex, have been extensively investigated to understand this process. In parallel to aiding in the understanding of oocyte biology, these features have been used to characterize an oocyte’s ability to achieve competence. In addition, oocytes undergo intense gene transcription and protein translation to accumulate the maternal stores. When the oocyte is fully grown, most genes are transcriptionally inactive, and the chromatin is densely compacted. More recently, RNA profiling has been used to further define the transcriptional parameters that are associated with oocyte development. Here, focusing on cattle, we provide an overview of the experimental models commonly used to understand the underlying biology related to oocyte developmental competence. We compiled public data and showed that cattle oocytes can express over 15 000 protein-coding genes, suggesting a complex transcriptome landscape. Surprisingly, less than 2% of the expressed genes have been linked to developmental competence. The identification of the gene products that contribute to oocyte development, and understanding their biological function, are a vital component of our quest toward defining oocyte developmental competence at the molecular level.
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Ritter, Lesley J., Satoshi Sugimura, and Robert B. Gilchrist. "Oocyte Induction of EGF Responsiveness in Somatic Cells Is Associated With the Acquisition of Porcine Oocyte Developmental Competence." Endocrinology 156, no. 6 (June 1, 2015): 2299–312. http://dx.doi.org/10.1210/en.2014-1884.
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Abstract Oocytes progressively acquire the competence to support embryo development as oogenesis proceeds with ovarian folliculogenesis. The objectives of this study were to investigate oocyte-secreted factor (OSF) participation in the development of somatic cell epidermal growth factor (EGF) responsiveness associated with oocyte developmental competence. A well-established porcine model was employed using oocytes from small (<4 mm) vs medium sized (>4 mm) antral follicles, representing low vs moderate developmental competence, respectively. Cumulus-oocyte complexes (COCs) were treated in vitro with inducers of oocyte maturation, and cumulus cell functions and oocyte developmental competence were assessed. COCs from small follicles responded to FSH but, unlike COCs from larger follicles, were incapable of responding to EGF family growth factors known to mediate oocyte maturation in vivo, exhibiting perturbed cumulus expansion and expression of associated transcripts (HAS2 and TNFAIP6). Low and moderate competence COCs expressed equivalent levels of EGF receptor (EGFR) mRNA; however, the former had less total EGFR protein leading to failed activation of phospho-EGFR and phospho-ERK1/2, despite equivalent total ERK1/2 protein levels. Native OSFs from moderate, but not from low, competence oocytes established EGF responsiveness in low competence COCs. Four candidate recombinant OSFs failed to mimic the actions of native OSFs in regulating cumulus expansion. Treatment with OSFs and EGF enhanced oocyte competence but only of the low competence COCs. These data suggest that developmental acquisition by the oocyte of capacity to regulate EGF responsiveness in the oocyte's somatic cells is a major milestone in the oocyte's developmental program and contributes to coordinated oocyte and somatic cell development.
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Pedersen, Hanne Skovsgaard, Peter Løvendahl, Knud Larsen, Lone Bruhn Madsen, and Henrik Callesen. "Porcine oocyte mtDNA copy number is high or low depending on the donor." Zygote 24, no. 4 (December 18, 2015): 617–23. http://dx.doi.org/10.1017/s0967199415000611.
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SummaryOocyte capacity is relevant in understanding decreasing female fertility and in the use of assisted reproductive technologies in human and farm animals. Mitochondria are important to the development of a functionally good oocyte and the oocyte mtDNA copy number has been introduced as a useful parameter for prediction of oocyte competence. The aim of this study was to investigate: (i) if the oocyte donor has an influence on its oocyte's mtDNA copy number; and (ii) the relation between oocyte size and mtDNA copy number using pre- and postpubertal pig oocytes. Cumulus–oocyte complexes were collected from individual donor pigs. The oocytes were allocated into different size-groups, snap-frozen and single-oocyte mtDNA copy number was estimated by quantitative real-time PCR using the genes ND1 and COX1. Results showed that mean mtDNA copy number in oocytes from any individual donor could be categorized as either ‘high’ (≥100,000) or ‘low’ (<100,000) with no difference in threshold between pre- and postpubertal oocytes. No linear correlation was detected between oocyte size and mtDNA copy number within pre- and postpubertal oocytes. This study demonstrates the importance of the oocyte donor in relation to oocyte mtDNA copy number, irrespectively of the donor's puberty status and the oocyte's growth stage. Observations from this study facilitate both further investigations of the importance of mtDNA copy number and the unravelling of relations between different mitochondrial parameters and oocyte competence.
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Petr, J., E. Chmelíková, K. Kheilová, and F. Jílek. "Histone deacetylase inhibition improves meiotic competence but not developmental competence in growing pig oocytes." Zygote 17, no. 4 (May 22, 2009): 307–14. http://dx.doi.org/10.1017/s0967199409005437.
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SummaryIn fully grown pig oocytes, meiotic maturation in vitro is retarded by inhibition of histone deacetylases by trichostatin A (TSA). In growing oocytes with partial meiotic competence, culture with TSA has no significant effect on the meiotic maturation. Growing oocytes treated with TSA mature mainly to metaphase I. The ratio of oocytes that mature to metaphase II is very limited. After transient exposure to TSA, the maturation of growing oocytes with partial meiotic competence takes a different course. When these oocytes are first cultured in a TSA-free medium, then cultured for another 24 h with 100 nM TSA and finally again in a TSA-free medium for 24 h, the ratio of oocytes that mature to metaphase II significantly increases reaching 59%. When oocytes were cultured for the same length of time without transient exposure to TSA, only 19% matured to metaphase II. Those oocytes that matured to metaphase II after transient exposure to TSA were successfully activated using calcium ionophore. However, the subsequent cleavage was very limited. We can conclude that transient exposure of growing pig oocytes with partial meiotic competence to TSA increases oocyte meiotic competence, but it does not enhance developmental competence after parthenogenetic activation.
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Rodriguez, Karina F., and Charlotte E. Farin. "Gene transcription and regulation of oocyte maturation." Reproduction, Fertility and Development 16, no. 2 (2004): 55. http://dx.doi.org/10.1071/rd03078.
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The developmental potential of an embryo is dependent on the developmental potential of the oocyte from which it originates. The process of oocyte maturation is critical for the efficient application of biotechnologies such as in vitro embryo production and mammalian cloning. However, the overall efficiency of in vitro maturation remains low because oocytes matured in vitro have a lower developmental competence than oocytes matured in vivo. Furthermore, oocytes that have been exposed to gonadotropins have greater developmental competence than oocytes matured in the absence of gonadotropins. By understanding the molecular mechanisms underlying gonadotropin-induced maturation, improvement in oocyte maturation technologies may be expected as procedures to manipulate specific factors involved in signalling for resumption of meiosis are identified. The present review will focus on transcriptional mechanisms underlying the maturation of mammalian oocytes in vitro, as well as on the acquisition of oocyte developmental competence. In addition, a working model for the transcriptional control of mammalian oocyte maturation is proposed.
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Feng, Wei Guo, and Zhi Fang Pan. "The Effect of Granulosa Cells Apoptosis on the Cumulus Expansion and the Developmental Competence of Bovine Oocytes." Advanced Materials Research 997 (August 2014): 251–54. http://dx.doi.org/10.4028/www.scientific.net/amr.997.251.
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In this study, we used the well in the well (WIW) culture system to study the effect of granulosa cells apoptosis on the cumulus expansion and the developmental competence of bovine oocytes. Results: The apoptosis of granulosa cells affect the cumulus expansion of bovine oocytes significantly. Especially when the percentage of granulosa cells apoptosis exceed 40%, the cumulus expansion was worse. The cumulus expansion affect the oocyte developmental competence of bovine oocytes significantly. The developmental competence of bovine oocyte increases with the increasing of cumulus expansion.
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Herrick, Jason R. "Reversible meiotic arrest in feline oocytes." Reproduction, Fertility and Development 26, no. 2 (2014): 258. http://dx.doi.org/10.1071/rd12341.
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Increasing intracellular concentrations of cyclic adenosine monophosphate (cAMP) within the cumulus–oocyte complex (COC) inhibits or delays spontaneous oocyte maturation and improves the developmental competence of the oocyte in many species, but information for carnivores is limited. The objectives of the present study were to describe the effects of isobutyl methylxanthine (IBMX), which decreases cAMP degradation, and forskolin, which increases cAMP production, on spontaneous and induced maturation (by equine chorionic gonadotrophin (eCG) and epidermal growth factor (EGF)) of feline oocytes and to evaluate the reversibility of IBMX-induced arrest by measuring the resumption of meiosis and embryonic development following IVF. IBMX decreased (P < 0.05) the incidence of spontaneous (6.7% vs 42.0%, metaphase II (MII)) and induced (5.6% vs 66.1% MII) maturation after 24 h of culture. In contrast, forskolin stimulated meiosis (81.7% MII; P < 0.05). Following 12 h of culture with IBMX and an additional 24 h with eCG and EGF in the absence of IBMX, the proportions of oocytes reaching MII (66.1%), cleaving (79.9%) and developing to the blastocyst stage (15.3%) were similar (P > 0.05) to oocytes cultured continuously with eCG and EGF (70.2%, 83.0% and 18.1%, respectively). These results demonstrate that IBMX reversibly inhibits both spontaneous and eCG+EGF-induced meiosis in feline oocytes without compromising the oocyte’s developmental competence.
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Pedersen, Hanne Skovsgaard, Henrik Callesen, Peter Løvendahl, Fenghua Chen, Jens Randel Nyengaard, Nanett Kvist Nikolaisen, Peter Holm, and Poul Hyttel. "Ultrastructure and mitochondrial numbers in pre- and postpubertal pig oocytes." Reproduction, Fertility and Development 28, no. 5 (2016): 586. http://dx.doi.org/10.1071/rd14220.
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Prepubertal pig oocytes are associated with lower developmental competence. The aim of this experiment was to conduct an exhaustive survey of oocyte ultrastructure and to use a design-unbiased stereological approach to quantify the numerical density and total number of mitochondria in oocytes with different diameters from pre- and postpubertal pigs. The ultrastructure of smaller prepubertal immature oocytes indicated active cells in close contact with cumulus cells. The postpubertal oocytes were more quiescent cell types. The small prepubertal oocytes had a lower total mitochondrial number, but no differences were observed in mitochondrial densities between groups. Mature postpubertal oocytes adhered to the following characteristics: presence of metaphase II, lack of contact between cumulus cells and oocyte, absence of rough endoplasmic reticulum and Golgi complexes, peripheral location of cortical granules and central localisation of mitochondria, vesicles and lipid droplets. Prepubertal oocytes displayed more variation. The ultrastructure of large pre- and postpubertal oocytes was compatible with higher developmental competence, whereas that of smaller prepubertal oocytes could explain their reduced capacity. The higher number of mitochondria in large pre- and postpubertal oocytes could have an influence on oocyte competence, by increasing the pool of mitochondria available for early embryonic development.
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Patel, Osman V., Anilkumar Bettegowda, James J. Ireland, Paul M. Coussens, Patrick Lonergan, and George W. Smith. "Functional genomics studies of oocyte competence: evidence that reduced transcript abundance for follistatin is associated with poor developmental competence of bovine oocytes." Reproduction 133, no. 1 (January 2007): 95–106. http://dx.doi.org/10.1530/rep.1.01123.
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Poor oocyte competence contributes to infertility in humans and livestock species. The molecular characteristics of such oocytes are generally unknown. Objectives of the present studies were to identify differences in RNA transcript abundance in oocytes and early embryos associated with reduced oocyte competence and development to the blastocyst stage. Microarray experiments were conducted using RNA isolated from germinal vesicle stage oocytes collected from adult versus prepubertal animals (model of poor oocyte competence). A total of 193 genes displaying greater mRNA abundance in adult oocytes and 223 genes displaying greater mRNA abundance in prepubertal oocytes were detected. Subsequent gene ontology analysis of microarray data revealed significant overrepresentation of transcripts encoding for genes in hormone secretion classification within adult oocytes and such genes were selected for further analysis. Real-time PCR experiments revealed greater abundance of mRNA for βA and βB subunits of inhibin/activin and follistatin, but not the α subunit in germinal vesicle stage oocytes collected from adult versus prepubertal animals. Cumulus cell follistatin and βB subunit mRNA abundance were similar in samples collected from prepubertal versus adult animals. A positive association between time of first cleavage (oocyte competence) and follistatin mRNA abundance was noted. Follistatin, βB, and α subunit mRNAs were temporally regulated during early bovine embryogenesis and peaked at the 16-cell stage. Collectively, results demonstrate a positive association of follistatin mRNA abundance with oocyte competence in two distinct models and dynamic regulation of follistatin, βB, and α subunit mRNAs in early embryos after initiation of transcription from the embryonic genome.
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Cai, L., E. Kim, S. U. Hwang, J. D. Yoon, Y. Jeon, E. Lee, and S. H. Hyun. "156 EFFECTS OF MORPHOLOGY TYPE OF POLAR BODY ON PORCINE OOCYTE QUALITY AND DEVELOPMENTAL POTENTIAL AFTER IN VITRO FERTILIZATION." Reproduction, Fertility and Development 26, no. 1 (2014): 192. http://dx.doi.org/10.1071/rdv26n1ab156.
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Evaluation of morphology of first polar body (1st PB) could be a method for the oocyte's quality and developmental competence. The developmental potential of oocyte with fragmented PB after in vitro maturation (IVM) is a controversial issue. The aim of this study is to investigate the effects of PB morphology type on oocyte quality and developmental competence after IVF. Porcine ovaries were obtained from prepubertal gilts at a local slaughterhouse and transported to the laboratory within 2 h in physiological saline supplemented with 100 IU mL–1 penicillin G and 100 mg mL–1 streptomycin sulfate. The cumulus–oocyte complexes (COC) were aspirated using an 18-gauge needle attached to a 10-mL disposable syringe from superficial follicles 3 to 6 mm in diameter followed by IVM. After IVM, oocytes were classified into 3 types as follows, oocytes with normal PB (A type), oocytes with a little of fragmented PB (B type), and oocytes with separated 2 PBs (C type), respectively. As classification of PB types, we analysed the distribution ratio of each PB type after IVM, and then performed IVF for analysis of fertilization rate and developmental potential. The ratio of oocyte with A type (73%) was significantly (P < 0.05) higher than that of B type (24.5%) or C type (2.5%) after IVM. Only mature oocytes were selected from A and B type and were subjected to IVF because of a small number of oocytes with C type. In the IVF experiment, the efficiency of monospermy and fertilization were significantly higher in oocytes of A type (46.7%) than those of type B (20.0%). The cleavage rate of oocytes with A type (63.9%) was significantly (P < 0.05) higher than the oocytes with B type (43.8%). Embryonic developmental competence to the blastocyst stage after IVF was significantly (P < 0.05) higher in the A-type oocytes (26.3%) than in the B-type oocytes (16.9%). The levels of glutathione and reactive oxygen species were not affected by the morphological classification of the PB. In summary, these results suggest that polar body morphology could be a marker of oocyte quality after IVM. We are currently studying gene expression of each oocytes and blastocysts. This work was supported, in part, by a grant from the Next-Generation BioGreen 21 Program (No. PJ00956901), Rural Development Administration, and the National Research Foundation of Korea Grant funded by the Korean Government (NRF-2012R1A1A4A01004885, NRF-2013R1A2A2A04008751), Republic of Korea.
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Takashima, Tomoya, Tsubasa Fujimaru, and Yayoi Obata. "Effect of in vitro growth on mouse oocyte competency, mitochondria and transcriptome." Reproduction 162, no. 4 (October 1, 2021): 307–18. http://dx.doi.org/10.1530/rep-21-0209.
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In vitro generation of fertile oocytes has been reported in several mammalian species. However, oocyte integrity is compromised by in vitro culture. Here, we aimed to understand the factors affecting oocyte competency by evaluating mitochondrial function and transcriptome as well as lipid metabolism in in vivo-derived oocytes and in vitro grown and matured (IVGM) oocytes under atmospheric (20%) and physiological (7%) O2 concentration. We used single-cell RNA-sequencing as well as Gene Ontology and KEGG analyses to identify the molecular pathways affecting the developmental competence of oocytes. Oocytes grown under 20% O2 conditions showed a significant decrease in mitochondrial membrane potential, upregulation of ceramide synthesis pathway-associated genes, and high ceramide accumulation compared with oocytes grown under 7% O2 conditions and in vivo-grown oocytes. This suggests that excess ceramide level causes mitochondrial dysfunction and poor developmental ability of the oocytes. Mitochondrial DNA copy number was lower in IVGM oocytes irrespective of O2 concentration in culture, although there was no common abnormality in the expression of genes related to mitochondrial biosynthesis. In contrast, some oocytes produced under 7% O2 conditions showed gene expression profiles similar to those of in vivo-grown oocytes. In these oocytes, the expression of transcription factors, including Nobox, was restored. Nobox expression correlated with the expression of genes essential for oocyte development. Thus, Nobox may contribute to the establishment of oocyte competency before and after the growth phase. The comprehensive analysis of IVGM oocytes presented here provides a platform for elucidating the mechanism underlying functional oocyte production in vivo.
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Pedersen, H. S., Y. Liu, R. Li, S. Purup, P. Løvendahl, P. Holm, P. Hyttel, and H. Callesen. "Selection of pre- versus postpubertal pig oocytes for parthenogenetic activation and somatic cell nuclear transfer." Reproduction, Fertility and Development 27, no. 3 (2015): 544. http://dx.doi.org/10.1071/rd13283.
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Pig oocytes have been used increasingly for in vitro production techniques in recent years. The slaughterhouse-derived oocytes that are often used are mostly of prepubertal origin. The aims of the present study were to compare the developmental competence between pre- and postpubertal pig oocytes, and to develop a simple and practical method for the selection of prepubertal pig oocytes for parthenogenetic activation (PA) and somatic cell nuclear transfer (SCNT) based on oocyte morphology after IVM and oocyte inside zona pellucida (ZP) diameter (‘small’ ≤110 µm; ‘medium’ >110 µm; ‘large’ ≥120 µm). Meiotic competence and blastocyst rates after PA and SCNT of prepubertal oocytes increased with oocyte size, with the large prepubertal oocytes reaching a level similar to postpubertal oocytes after SCNT. Blastocyst cell number was not related to oocyte inside ZP diameter and oocyte donor to the same extent as blastocyst rate. Very low blastocyst rates were obtained after PA of morphologically bad pre- and postpubertal oocytes. In conclusion, measurement of inside ZP diameter combined with morphological selection is useful to remove incompetent oocytes. Further studies are needed to clarify the relative importance of cytoplasmic volume and stage in oocyte growth phase.
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Thuy Van, Nguyen Thi, Pham Truong Duy, Nguyen Van Thuan, and Bui Hong Thuy. "Caffeine improves the developmental competence of parthenogenetic embryos derived from aging porcine oocytes." Vietnam Journal of Biotechnology 17, no. 4 (November 2, 2020): 629–36. http://dx.doi.org/10.15625/1811-4989/17/4/14187.
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Oocytes are committed to deterioration in quality as they aged due to a long duration manipulation which leads to the reduced success rate of somatic cell nuclear transfer (SCNT). Caffeine with an effect to maintain the maturation-promoting factor (MPF) from the metaphase of oocytes is expected to enhance the quality of the aging oocytes. To investigate the timely treatment of caffeine to rescue aging oocytes, caffeine was supplemented after in vitro maturation (IVM) or during metaphase I – metaphase II (MI – MII) transition. First, the effect of caffeine after IVM of oocytes was examined. After IVM for 42 h, oocytes were left for aging within 6 or 8 hours in supplement with various concentrations of caffeine (0, 5 and 10 mM), and then, examined the quality of embryo from aged oocyte through parthenogenesis activation. We found that 5 mM caffeine for the first 6 hours of aging process was suggested to improve the early development of parthenogenetic diploid embryos. However, the cytoplasmic homogeneity is significantly reduced in aging oocyte compared to fresh oocyte and it could not be improved by caffeine treatment. Next, the effect of caffeine during MI – MII transition of oocyte was examined. Caffeine was supplemented during MI – MII transition (27 – 42 h) of IVM. Then mature oocytes were left for aging within 6 h to examine on aging porcine oocyte quality via parthenogenesis embryos. The results indicated that 5 mM caffeine during MI-MII transition could efficiently rescue aged oocytes and improve the development of embryos derived from aging oocytes to four-cell, eight-cell and blastocyst stage as compared to fresh oocytes. Especially, these aged oocytes treated by caffeine could improve the cytoplasmic homogeneity in embryos and the quality of blastocysts by increasing cell number similar to fresh oocytes.
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Metcalf, Elizabeth S., Keith R. Masterson, David Battaglia, Jeremy G. Thompson, Robert Foss, Richard Beck, Nancy L. Cook, and Thomas O'Leary. "Conditions to optimise the developmental competence of immature equine oocytes." Reproduction, Fertility and Development 32, no. 11 (2020): 1012. http://dx.doi.org/10.1071/rd19249.
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Optimising the developmental potential of immature equine oocytes and invitro-produced (IVP) embryos was explored through modifications of established media and holding temperature. In Experiment 1, delaying spontaneous resumption of meiosis through the process of simulated physiological oocyte maturation with the addition of the adenylate cyclase activator forskolin (50µM) and the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (100µM) to overnight holding medium before maturation improved blastocyst production (P<0.05). In Experiment 2, the blastocyst production rate was increased significantly when cumulin (100ng mL−1) was added to the overnight holding or culture media (P<0.05). In Experiment 3, immature oocytes held overnight at 16°C before maturation had improved developmental competence than those held at 20°C and 5°C (P<0.05). There was no difference between maturation rates, but blastocyst formation per cleaved oocyte was significantly greater in oocytes held overnight at 16°C than at 20°C or 5°C. Furthermore, blastocyst formation per recovered oocyte and per fertilised oocyte was greater when oocytes were held before maturation at 16°C than at 5°C (P<0.05). In Experiment 4, the addition of sodium ascorbate (AC; 50µg mL−1) to the maturation and/or culture media of oocytes and IVP embryos did not improve blastocyst production, but did appear to lower cleavage rates compared with oocytes and embryos cultured without AC.
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Taiyeb, A. M., S. A. Muhsen-Alanssari, M. E. Kjelland, S. M. Taiyeb, A. I. Haji, D. C. Kraemer, and M. T. Ridha-Albarzanchi. "65 OVULATION OF IMMATURE OOCYTES WITH HIGH COMPETENCE RATES." Reproduction, Fertility and Development 29, no. 1 (2017): 140. http://dx.doi.org/10.1071/rdv29n1ab65.
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Collection of immature oocytes from antral follicles in superovulated mice is a widely established technique for retrieval of germinal vesicle (GV) and metaphase I (MI) oocytes. Investigators use their experience to select antral follicles under a microscope before puncturing the follicles. This is sometimes followed by screening of oocytes based on morphology and diameter, and usually mouse oocytes of small diameters or abnormal morphologies are excluded. Shortcomings with the current technique may include varied oocyte yields and collection of oocytes from primary and secondary follicles. Moreover, such immature oocytes were observed to have different chromatin configurations, cortical granule distributions, spindle-chromosome organizations, fertilization rates, and diameters. This study was designed to investigate the potential of ovulated immature oocytes, resultant from superovulated mice treated with an FDA approved phosphodiesterase 3A inhibitor named cilostazol (CLZ), to substitute for ovarian immature oocytes collected from antral follicles of superovulated mice. Swiss Webster mice were superovulated and gavaged with 7.5 mg of CLZ once, at the same time as hCG injection, or twice, at the same time as hCG plus 6 h post-hCG injection, to result in ovulation of MI or GV oocytes, respectively. Control ovarian GV or MI oocytes were collected from ovarian antral follicles of superovulated mice not treated with CLZ. Ten mice were used in each treatment or control group. Single or multiple administrations of CLZ resulted in mice ovulating 85.8 ± 3.9% MI oocytes or 95.2 ± 3% GV oocytes (mean ± SEM), respectively. Treated GV oocytes had significantly higher rates of advanced chromatin configuration and cortical granule distribution than did control GV oocytes. Treated GV oocytes had lower cAMP levels and higher rates of meiotic maturation, IVF, and blastocyst formation than did control GV oocytes (P < 0.0001). Treated MI oocytes had significantly higher rates of normal spindle and chromosomes aligned at the metaphase plates and offspring than did control MI oocytes. Control or treated GV oocytes were found to have greater diameters than did control or treated MI oocytes, respectively (P < 0.007), indicating that initiation of meiotic maturation is associated with reduction in oocyte diameters and utilisation of cytoplasm proteins and cofactors. Moreover, control GV oocytes were found to have greater diameters than did treated GV oocytes (P = 0.007). This may refer to the readiness of treated GV oocytes to undergo germinal vesicle breakdown and transition into the MI stage, especially treated GV oocytes had high rates of meiotic development in comparison to control GV oocytes. Diameters of GV nuclei in treated GV oocytes were smaller than those in control GV oocytes (P = 0.006), which may also indicate a germinal vesicle that had started to undergo germinal vesicle breakdown. A similar significant difference was also noted with control and treated MI oocytes. In summary, we present a novel method for retrieval of immature oocytes at different stages of meiotic maturation. Treated ovulated immature oocytes had more uniform diameters and high developmental competence than did ovarian immature oocytes. Treated ovulated immature oocytes may substitute for ovarian immature oocytes and become an additional research resource.
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Pontelo, Thais P., Sarah A. D. Rodrigues, Taynan S. Kawamoto, Ligiane O. Leme, A. C. M. M. Gomes, Marcio G. Zangeronimo, Mauricio M. Franco, and Margot A. N. Dode. "Histone acetylation during the in vitro maturation of bovine oocytes with different levels of competence." Reproduction, Fertility and Development 32, no. 7 (2020): 690. http://dx.doi.org/10.1071/rd19218.
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We aimed to analyse the histone acetylation status and expression profile of genes involved in histone acetylation (histone acetyltransferase 1 (HAT1), lysine acetyltransferase 2A (KAT2A), histone deacetylase 1(HDAC1), HDAC2 and HDAC3) in bovine oocytes of different competences during invitro maturation (IVM). Cumulus–oocyte complexes were recovered from two groups of follicles: minor follicles (1.0–3.0mm in diameter), classified as low competence (LC) and large follicles (6.0–8.0mm in diameter) classified as high competence (HC). Oocytes were submitted to IVM for 0, 8 and 24h and stored for analysis. Acetylation status of histone H4 on lysine K5, K6, K12 and K16 was assessed by immunohistochemistry. For gene expression, mRNA levels were determined by real-time quantitative polymerase chain reaction. All oocytes, regardless of their competence, showed a gradual decrease (P<0.05) in acetylation signals during IVM. From 0 to 8h of maturation, an increase (P<0.05) in the relative abundance of HAT1 mRNA was observed only in the HC oocytes. In this group, higher (P<0.05) mRNA levels of HDAC1 at 8h of maturation were also observed. In conclusion, in the present study, LC oocytes were shown to have adequate acetylation levels for the resumption and progression of meiosis; however, these oocytes do not have the capacity to synthesise RNA during IVM as the HC oocytes do.
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Grupen, Christopher G., Stephen M. McIlfatrick, Rodney J. Ashman, Andrew C. Boquest, David T. Armstrong, and Mark B. Nottle. "Relationship between donor animal age, follicular fluid steroid content and oocyte developmental competence in the pig." Reproduction, Fertility and Development 15, no. 2 (2003): 81. http://dx.doi.org/10.1071/rd02086.
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The developmental competence of oocytes recovered from the ovaries of slaughtered prepubertal and adult pigs was evaluated after in vitro maturation, parthenogenetic activation and culture in vitro. In addition, the effect of prepubertal and adult follicular fluid (FF) on the developmental competence of prepubertal and adult oocytes was investigated. When matured in adult FF, the rates of cleavage (92 v. 73%; P < 0.01) and blastocyst formation (57 v. 38%; P < 0.05) were greater for adult oocytes than for prepubertal oocytes. Blastocysts derived from adult oocytes had more trophectoderm cells (43 v. 30; P < 0.05) and total cells (51 v. 36; P < 0.05) than blastocysts derived from prepubertal oocytes. The developmental competence of prepubertal oocytes was not affected by the FF donor age, whereas the developmental competence of adult oocytes was. Blastocysts derived from adult oocytes matured in adult FF had more trophectoderm cells (38 v. 24; P < 0.005), inner cell mass cells (7 v. 3; P < 0.01) and total cells (45 v. 27; P < 0.001) than blastocysts derived from adult oocytes matured in prepubertal FF. Characterization of the steroid content of the FF used to supplement the maturation medium revealed that adult FF contained more progesterone (42 v. 23 ng mL−1; P < 0.005) and androstenedione (70 v. 16 ng mL−1; P < 0.05) than prepubertal FF. In addition, the molar ratios of progesterone to androstenedione, androstenedione to 17β-oestradiol and androstenedione to testosterone differed (P < 0.05) between prepubertal and adult FF. The results support the hypothesis that a greater proportion of adult oocytes than of prepubertal oocytes has completed ‘oocyte capacitation’. The differences in FF steroid content are indicative of the different follicular environments from which the prepubertal and adult oocytes were isolated, and may be attributed to the observed effects on oocyte developmental competence.
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Raghu, H. M., S. Nandi, and S. M. Reddy. "Follicle size and oocyte diameter in relation to developmental competence of buffalo oocytes in vitro." Reproduction, Fertility and Development 14, no. 1 (2002): 55. http://dx.doi.org/10.1071/rd01060.
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Follicular size, oocyte morphology and diameter were investigated for their possible relationship with in vitro developmental competence of buffalo oocytes. Cumulus oocytes complexes (COCs), aspirated from small (<3 mm), medium (3–8 mm) and large (>8 mm) follicles of normal ovaries and cystic ovarian follicles of abattoir-derived ovaries, were graded for their morphological appearance and were cultured to assess their developmental competence. The influence of cystic follicles on maturational competence of COCs recovered from co-existing follicles of cystic ovaries was studied. The mean diameter of oocytes from follicles of different size were examined, and the influence of oocyte diameter—(i) <126 m; (ii) 127–144 m; (ii) 145–162 m; and (iv) >163 m—on in vitro maturation, cleavage and embryo yield was studied. Results suggested that increased fertilization, cleavage and embryo development were significantly (P<0.05) higher in COCs aspirated from large follicles, followed by medium and small-sized normal follicles, and the presence of cystic follicles had no significant (P<0.05) effect on the maturation competence of the COCs recovered from co-existing follicles. The mean diameter of the buffalo oocyte obtained from normal ovaries was found to be 146.4 m and the rate of blastocyst production in vitro was significantly higher (P<0.05) in oocytes with diameters greater than 145 m. In conclusion, the larger the size of the follicles and oocytes, the greater the developmental competence in vitro of buffalo oocytes.
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Bellone, Michele, Maurizio Zuccotti, Carlo Alberto Redi, and Silvia Garagna. "The position of the germinal vesicle and the chromatin organization together provide a marker of the developmental competence of mouse antral oocytes." REPRODUCTION 138, no. 4 (October 2009): 639–43. http://dx.doi.org/10.1530/rep-09-0230.
Full textAbstract:
Based on their chromatin organization, antral oocytes can be classified into two classes, namely surrounded nucleolus (SN, chromatin forms a ring around the nucleolus), and not surrounded nucleolus (NSN, chromatin has a diffuse pattern). Oocytes of both classes are capable of meiotic resumption, but while SN oocytes, following fertilization, develop to term, NSN oocytes never develop beyond the two-cell stage. A recent study has shown that the position of the germinal vesicle (GV) can be used as a morphological marker predictive of oocyte meiotic competence, i.e. oocytes with a central GV have a higher meiotic competence than oocytes with an eccentric GV. In the present study, we have associated both markers with the aim of identifying, with more accuracy, the oocytes' developmental competence. Following their isolation, antral oocytes were classified on the basis of both SN and NSN chromatin configuration and their GV position, matured to metaphase II and fertilized in vitro. We demonstrated that the position of the GV is a good marker to predict the oocytes' developmental competence, but only when associated with the observation of the chromatin organization.
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Mohammadi-Sangcheshmeh, Abdollah, Eva Held, Franca Rings, Nasser Ghanem, Dessie Salilew-Wondim, Dawit Tesfaye, Harald Sieme, Karl Schellander, and Michael Hoelker. "Developmental competence of equine oocytes: impacts of zona pellucida birefringence and maternally derived transcript expression." Reproduction, Fertility and Development 26, no. 3 (2014): 441. http://dx.doi.org/10.1071/rd12303.
Full textAbstract:
In the present study, equine oocytes were classified into groups of presumably high and low developmental competence according to cumulus morphology, as well as oocyte ability to metabolise brilliant cresyl blue (BCB) stain. All oocytes were evaluated individually in terms of morphometry, zona pellucida birefringence (ZPB) and relative abundance of selected candidate genes. Oocytes with an expanded cumulus (Ex), representing those with presumably high developmental competence, had a significantly thicker zona (18.2 vs 17.3 µm) and a significantly higher ZPB (64.6 vs 62.1) than oocytes with a compacted cumulus (Cp). Concurrently, oocytes classified as highly developmentally competent (BCB+) had a significantly thicker zona (18.8 vs 16.1 µm) and significantly higher ZPB (63.1 vs 61.3) compared with oocytes classified as having low developmental competence. Expression of TFAM, STAT3 and CKS2 was significantly higher in Ex compared with Cp oocytes, whereas expression of COX1, ATPV6E and DNMT1 was lower. Together, the data reveal that developmentally competent equine oocytes are larger in size, have higher ZPB values and exhibit a typical genetic signature of maternally derived transcripts compared with oocytes with lower in vitro developmental competence.
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Kordowitzki, Paweł, Gabriela Sokołowska, Marta Wasielak-Politowska, Agnieszka Skowronska, and Mariusz T. Skowronski. "Pannexins and Connexins: Their Relevance for Oocyte Developmental Competence." International Journal of Molecular Sciences 22, no. 11 (May 31, 2021): 5918. http://dx.doi.org/10.3390/ijms22115918.
Full textAbstract:
The oocyte is the major determinant of embryo developmental competence in all mammalian species. Although fundamental advances have been generated in the field of reproductive medicine and assisted reproductive technologies in the past three decades, researchers and clinicians are still trying to elucidate molecular factors and pathways, which could be pivotal for the oocyte’s developmental competence. The cell-to-cell and cell-to-matrix communications are crucial not only for oocytes but also for multicellular organisms in general. This latter mentioned communication is among others possibly due to the Connexin and Pannexin families of large-pore forming channels. Pannexins belong to a protein group of ATP-release channels, therefore of high importance for the oocyte due to its requirements of high energy supply. An increasing body of studies on Pannexins provided evidence that these channels not only play a role during physiological processes of an oocyte but also during pathological circumstances which could lead to the development of diseases or infertility. Connexins are proteins that form membrane channels and gap-junctions, and more precisely, these proteins enable the exchange of some ions and molecules, and therefore they do play a fundamental role in the communication between the oocyte and accompanying cells. Herein, the role of Pannexins and Connexins for the processes of oogenesis, folliculogenesis, oocyte maturation and fertilization will be discussed and, at the end of this review, Pannexin and Connexin related pathologies and their impact on the developmental competence of oocytes will be provided.
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Caixeta, Ester Siqueira, Paula Ripamonte, Maurício Machaim Franco, José Buratini Junior, and Margot Alves Nunes Dode. "Effect of follicle size on mRNA expression in cumulus cells and oocytes of Bos indicus: an approach to identify marker genes for developmental competence." Reproduction, Fertility and Development 21, no. 5 (2009): 655. http://dx.doi.org/10.1071/rd08201.
Full textAbstract:
To identify the genes related to oocyte competence, we quantified transcripts for candidate genes in oocytes (H1Foo, H2A, H3A, GHR, GDF9, BMP15, OOSP1) and cumulus cells (FSHR, EGFR, GHR, PTX3, IGFII) using the follicle size model to select oocytes of better developmental quality. Follicles were dissected and distributed into four groups according to diameter as follows: 1.0–3.0, 3.1–6.0, 6.1–8.0 and ≥8.1 mm. Cumulus–oocyte complexes (COCs) were released, classified morphologically, matured, fertilised and cultured in vitro or denuded for measurement of diameter and determination of gene expression. Denuded germinal vesicle oocytes and their cumulus cells were used for gene expression analysis by reverse transcription–polymerase chain reaction. The blastocyst rate was highest for oocytes recovered from follicles >6 mm in diameter. In the oocyte, expression of the H2A transcript only increased gradually according to follicle size, being greater (P < 0.05) in oocytes from follicles ≥8.1 mm in diameter than in oocytes from follicles <6.0 mm in diameter. In cumulus cells, expression of FSHR, EGFR and GHR mRNA increased with follicular size. In conclusion, we confirmed the importance of H2A for developmental competence and identified important genes in cumulus cells that may be associated with oocyte competence.
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Redel, Bethany K., Lee D. Spate, Ye Yuan, Clifton N. Murphy, R. Michael Roberts, and Randall S. Prather. "Neither gonadotropin nor cumulus cell expansion is needed for the maturation of competent porcine oocytes in vitro†." Biology of Reproduction 105, no. 2 (May 7, 2021): 533–42. http://dx.doi.org/10.1093/biolre/ioab090.
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Abstract In-vitro maturation (IVM) of oocytes from immature females is widely used in assisted reproductive technologies. Here we illustrate that cumulus cell (CC) expansion, once considered a key indicator of oocyte quality, is not needed for oocytes to mature to the metaphase II (MII) stage and to gain nuclear and cytoplasmic competence to produce offspring. Juvenile pig oocytes were matured in four different media: (1) Basal (−gonadotropins (GN) − FLI); (2) −GN + FLI (supplement of FGF2, LIF, and IGF1); (3) +GN − FLI; and (4) +GN + FLI. There was no difference in maturation to MII or progression to the blastocyst stage after fertilization of oocytes that had been matured in −GN + FLI medium and oocytes matured in +GN + FLI medium. Only slight CC expansion occurred in the two media lacking GN compared with the two where GN was present. The cumulus-oocytes-complexes (COC) matured in +GN + FLI exhibited the greatest expansion. We conclude that FLI has a dual role. It is directly responsible for oocyte competence, a process where GN are not required, and, when GN are present, it has a downstream role in enhancing CC expansion. Our study also shows that elevated phosphorylated MAPK may not be a necessary correlate of oocyte maturation and that the greater utilization of glucose by COC observed in +GN + FLI medium probably plays a more significant role to meet the biosynthetic needs of the CC to expand than to attain oocyte developmental competence. Gene expression analyses have not been informative in providing a mechanism to explain how FLI medium enhances oocyte competence without promoting CC expansion.
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Hamatani, Toshio, Mitsutoshi Yamada, Hidenori Akutsu, Naoaki Kuji, Yoshiyuki Mochimaru, Mitsuko Takano, Masashi Toyoda, Kenji Miyado, Akihiro Umezawa, and Yasunori Yoshimura. "What can we learn from gene expression profiling of mouse oocytes?" REPRODUCTION 135, no. 5 (May 2008): 581–92. http://dx.doi.org/10.1530/rep-07-0430.
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Mammalian ooplasm supports the preimplantation development and reprograms the introduced nucleus transferred from a somatic cell to confer pluripotency in a cloning experiment. However, the underlying molecular mechanisms of oocyte competence remain unknown. Recent advances in microarray technologies have allowed gene expression profiling of such tiny specimens as oocytes and preimplantation embryos, generating a flood of information about gene expressions. So, what can we learn from it? Here, we review the initiative global gene expression studies of mouse and/or human oocytes, focusing on the lists of maternal transcripts and their expression patterns during oogenesis and preimplantation development. Especially, the genes expressed exclusively in oocytes should contribute to the uniqueness of oocyte competence, driving mammalian development systems of oocytes and preimplantation embryos. Furthermore, we discuss future directions for oocyte gene expression profiling, including discovering biomarkers of oocyte quality and exploiting the microarray data for ‘making oocytes’.
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Zhang, Kun, Peter J. Hansen, and Alan D. Ealy. "Fibroblast growth factor 10 enhances bovine oocyte maturation and developmental competence in vitro." REPRODUCTION 140, no. 6 (December 2010): 815–26. http://dx.doi.org/10.1530/rep-10-0190.
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The ability of oocytes to resume meiosis, become fertilized, and generate viable pregnancies is controlled during folliculogenesis by several endocrine and paracrine factors. The aim of this work is to determine whether fibroblast growth factor 10 (FGF10) is an oocyte competent factor. Transcripts for each of the four FGF receptor types (FGFR) were present in cumulus and oocytes after their extraction from the follicles. FGFR1 transcripts predominated in cumulus cells whereas FGFR2 was most abundant in oocytes. Exposing the cumulus–oocyte complexes to FGF10 duringin vitromaturation did not affect cleavage rates, but increases (P<0.05) in the percentage of embryos at the 8–16-cell stage on day 3 and at the blastocyst stage on day 7, which were evident in FGF10-supplemented oocytes. The progression of oocytes through meiosis and cumulus expansion was increased (P<0.05) by FGF10. The importance of the endogenous sources of FGFs was examined by adding anti-FGF10 IgG during oocyte maturation. Blocking endogenous FGF10 activity decreased (P<0.05) the percentage of oocytes developing into blastocysts and limited (P<0.05) cumulus expansion. Expression profiles of putative cumulus and oocyte competency markers were examined for their involvement in FGF10-mediated responses. FGF10 influenced the expression ofCTSBandSPRY2in cumulus cells andBMP15in oocytes. In summary, this work provides new insight into the importance of FGFRs and locally derived FGF10 during oocyte maturation in cattle. Its subsequent impact onin vitroembryo development implicates it as a noteworthy oocyte competent factor.
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Tharasanit, T., S. Colleoni, G. Lazzari, B. Colenbrander, C. Galli, and T. A. E. Stout. "Effect of cumulus morphology and maturation stage on the cryopreservability of equine oocytes." Reproduction 132, no. 5 (November 2006): 759–69. http://dx.doi.org/10.1530/rep.1.01156.
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Oocyte cryopreservation is a potentially valuable way of preserving the female germ line. However, the developmental competence of cryopreserved oocytes is presently poor. This study investigated whether the morphology of the cumulus complex surrounding an immature equine oocyte and/or the oocyte’s stage of maturation affect its cryopreservability. Compact (Cp) and expanded (Ex) cumulus oocyte complexes (COCs) were vitrified either shortly after recovery (germinal vesicle stage, GV) or after maturation in vitro (IVM); cryoprotectant-treated and -untreated non-frozen oocytes served as controls. In Experiment I, oocytes matured in vitro and then vitrified, or vice versa, were examined for maturation stage and meiotic spindle quality. Cp and Ex COCs vitrified at the GV stage matured at similar rates during subsequent IVM (41 vs 46% MII), but meiotic spindle quality was better for Cp than Ex (63 vs 33% normal spindles). Vitrifying oocytes after IVM resulted in disappointing post-warming spindle quality (32 vs 28% normal for Cp vs Ex). In Experiment II, oocytes from Cp and Ex COCs vitrified at the GV or MII stages were fertilized by intracytoplasmic sperm injection (ICSI) and monitored for cleavage and blastocyst formation. Oocytes vitrified prior to IVM yielded higher cleavage rates (34 and 27% for Cp and Ex COCs) than those vitrified after IVM (16 and 4%). However, only one blastocyst was produced from a sperm-injected vitrified–warmed oocyte (0.4 vs 9.3% and 13% blastocysts for cryoprotectant-exposed and -untreated controls). It is concluded that, when vitrification is the chosen method of cryopreservation, Cp equine COCs at the GV stage offer the best chance of an MII oocyte with a normal spindle and the potential for fertilization; however, developmental competence is still reduced dramatically.
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Valleh, Mehdi Vafaye, Mikkel Aabech Rasmussen, and Poul Hyttel. "Combination effects of epidermal growth factor and glial cell line-derived neurotrophic factor on the in vitro developmental potential of porcine oocytes." Zygote 24, no. 3 (September 9, 2015): 465–76. http://dx.doi.org/10.1017/s0967199415000416.
Full textAbstract:
SummaryThe developmental potential of in vitro matured porcine oocytes is still lower than that of oocytes matured and fertilized in vivo. Major problems that account for the lower efficiency of in vitro production include the improper nuclear and cytoplasmic maturation of oocytes. With the aim of improving this issue, the single and combined effects of epidermal growth factor (EGF) and glial cell line-derived neurotrophic factor (GDNF) on oocyte developmental competence were investigated. Porcine cumulus–oocyte cell complexes (COCs) were matured in serum-free medium supplemented with EGF (0, 10 or 50 ng/ml) and/or GDNF (0, 10 or 50 ng/ml) for 44 h, and subsequently subjected to fertilization and cultured for 7 days in vitro. The in vitro-formed blastocysts derived from selected growth factor groups (i.e. EGF = 50 ng/ml; GDNF = 50 ng/ml; EGF = 50 ng/ml + GDNF = 50 ng/ml) were also used for mRNA expression analysis, or were subjected to Hoechst staining. The results showed that the addition of EGF and/or GDNF during oocyte maturation dose dependently enhanced oocyte developmental competence. Compared with the embryos obtained from control or single growth factor-treated oocytes, treatment with the combination of EGF and GDNF was shown to significantly improve oocyte competence in terms of blastocyst formation, blastocyst cell number and blastocyst hatching rate (P < 0.05), and also simultaneously induced the expression of BCL-xL and TERT and suppressed the expression of caspase-3 in resulting blastocysts (P < 0.05). These results suggest that both GDNF and EGF may play an important role in the regulation of porcine in vitro oocyte maturation and the combination of these growth factors could promote oocyte competency and blastocyst quality.
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Obata, Y., and T. Kono. "254 DEVELOPMENTAL COMPETENCE OF MOUSE OOCYTES AFTER IN VITRO GROWTH, NUCLEAR TRANSFER, AND IN VITRO FERTILIZATION." Reproduction, Fertility and Development 19, no. 1 (2007): 243. http://dx.doi.org/10.1071/rdv19n1ab254.
Full textAbstract:
Long-term effects of in vitro maturation of oocytes and in vitro culture of fertilized eggs have been reported in ruminants, mice, and humans. However, effects of in vitro oocyte growth are unknown. Although a large number of non-growing oocytes can be a gamete resource, very few oocytes ever acquire competence to support full-term development after in vitro growth. The objective of the study was to evaluate different culture conditions and the long-term effects of in vitro oocyte growth on the production of offspring. Oocytes of newborn, 10-day-old, and adult BDF1 (C57BL/6N � DBA2) mice were cultured for 22, 11, and 1 day(s), respectively. The results showed that alpha-MEM medium was superior to Waymouth medium in oocyte growth (68.6 � 3.87 �m vs. 61.7 � 3.26 �m, respectively; P < 0.001), and in maintenance of follicular integrity (69% vs. 30%; P < 0.001) when non-growing oocytes from newborn mice were cultured. However, oocytes grown in vitro were incompetent to support meiotic maturation by themselves in the case of either the 22-day culture of oocytes from newborn mice (1/59 in alpha-MEM vs. 1/65 in Waymouth) or the 11-day culture of oocytes from 10-day-old mice (51/140 in alpha-MEM vs. 2/157 in Waymouth), and none of them developed to the blastocyst stage. Subsequently, to examine the nucleic competence of oocytes grown in vitro, serial nuclear transfers were carried out. Karyoplasts from oocytes grown in vitro using alpha-MEM were fused with the GV oocytes grown in vivo after enucleation. The reconstituted oocytes were cultured in alpha-MEM. After 14 h, MII chromosomes of the reconstituted oocytes were transferred into the enucleated and ovulated MII oocytes in order to provide cytoplasmic competency. The results showed that when the donor oocytes attained a diameter of e60 �m, the reconstituted oocytes could develop into pups at extremely high rates (30-41%) after in vitro fertilization (IVF) and embryo transfer in the case of either the 22-day culture of oocytes from newborn mice (7/17) or the 11-day culture of oocytes from 10-day-old mice (25/77). A significant difference was not observed in the competence to develop to term of the reconstituted oocytes when compared with that of the oocytes reconstituted from the control GV (25/52; P > 0.05). When the donor oocytes attained a diameter of 50–60 �m, the reconstituted oocytes also could develop into pups (7/33); however, their efficiency was significantly reduced when compared with that of the reconstituted oocytes from the control GV (P < 0.05). On the other hand, the weight of the offspring depended on the duration of culture, and offspring from non-growing oocytes (1.48 � 0.17 g) were heavier than those of the IVF control (1.25 � 0.14 g; P < 0.05). In conclusion, we have demonstrated that using a nuclear transfer technique combined with in vitro growth of oocytes was sufficient to produce functional oocytes, and long-term culture for oocyte growth did not affect the nucleic ability of oocytes to develop to term; however, fetal growth may be susceptible to the duration of culture.
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Wang, Xia, Jason E. Swain, Mathieu Bollen, Xiao-Tie Liu, Dana A. Ohl, and Gary D. Smith. "Endogenous regulators of protein phosphatase-1 during mouse oocyte development and meiosis." Reproduction 128, no. 5 (November 2004): 493–502. http://dx.doi.org/10.1530/rep.1.00173.
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Reversible phosphorylation, involving protein kinases and phosphatases (PP), is important in regulating oocyte meiosis. Okadaic acid (OA) inhibition of PP1 and/or PP2A stimulates oocyte germinal vesicle breakdown (GVB). In oocytes, PP1 is localized in the cytoplasm and nucleus, yet endogenous regulation of oocyte PP1 has not been investigated. The objectives of the study were to identify intra-oocyte mechanisms regulating PP1 during acquisition of OA-sensitive meiotic competence and meiotic resumption. Immunohistochemical studies revealed that GVB-incompetent oocytes contained equivalent cytoplasmic and nuclear PP1. Upon development of OA-sensitive meiotic competence, PP1 displayed differential intracellular localization with significantly greater nuclear staining with distinct nucleolar rimming compared with cytoplasmic staining. Germinal vesicle-intact oocytes contained neither nuclear inhibitor of PP1, nor PP1 cytoplasmic inhibitor-1 transcripts or proteins. Reverse transcription-PCR with PP1 cytoplasmic inhibitor-2 (I2) primers and oocyte RNA amplified a predicted 330-bp product with the identical sequence to mouse liver I2. Oocytes contained a heat-stable PP1 inhibitor with biochemical properties of I2. Phosphorylation of PP1 at Thr320 by cyclin dependent kinase-1 (CDK1) causes PP1 inactivation. Germinal vesicle-intact oocytes did not contain phospho-Thr320-PP1. Upon GVB, PP1 became phosphorylated at Thr320 and this phosphorylation did not occur if GVB was blocked with the CDK1 inhibitor, roscovitine (ROSC). Inhibition of oocyte GVB with ROSC was reversible and coincided with PP1 phosphorylation at Thr320. Increased oocyte staining of nuclear PP1 compared with cytoplasmic staining at a chronological stage when oocytes gain meiotic competence, and phosphorylation and inhibition of PP1 by CDK1 at or around GVB appear to be important mechanisms in regulating oocyte PP1 activity and meiosis. In addition, these studies provide further support for PP1 being the OA-sensitive PP important in the regulation of the acquisition of meiotic competence, nuclear events during meiotic arrest, and GVB.
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Roelen, Bernard A. J. "Bovine oocyte maturation: acquisition of developmental competence." Reproduction, Fertility and Development 32, no. 2 (2020): 98. http://dx.doi.org/10.1071/rd19255.
Full textAbstract:
Although millions of oocytes are formed during embryo and fetal development in the cow, only a small fraction of these will form a developmentally competent oocyte and be fertilised. Development to competence relies on an intimate contact between the oocyte and the surrounding somatic cells in ovarian follicles, via both direct cell–cell contact and paracrine signalling. An important aspect of oocyte maturation is the segregation of homologous chromosomes and subsequently sister chromatids to form a haploid oocyte. Furthermore, the cytoplasm needs to be prepared for the formation of pronuclei and nuclear reprogramming to form a totipotent zygote. Conditions such as high levels of fatty acids or oxidative stress constrain the developmental competence of oocytes, and a better insight into these processes may help improve in vitro and in vivo oocyte maturation success. In addition, identification of the developmentally competent oocyte is useful for the efficiency of (artificial) reproduction.
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Higaki, Shogo, Masao Kishi, Keisuke Koyama, Masashi Nagano, Seiji Katagiri, Tatsuyuki Takada, and Yoshiyuki Takahashi. "Early germinal vesicle breakdown is a predictor of high preimplantation developmental competent oocytes in mice." Zygote 25, no. 1 (November 22, 2016): 41–48. http://dx.doi.org/10.1017/s0967199416000290.
Full textAbstract:
SummaryThe preselection of highly developmentally competent oocytes for in vitro maturation (IVM) is crucial for improving assisted reproductive technology. Although several intrinsic markers of oocyte quality are known to be closely related to the onset of nuclear maturation (germinal vesicle break down, GVBD), a direct comparison between GVBD timing and oocyte quality has never been reported. In this study, we established a non-invasive oocyte evaluation method based on GVBD timing for preselecting more developmental competent oocytes in mice. Because the O2 concentration during IVM may affect the nuclear kinetics, all experiments were performed under two distinct O2 concentrations: 20% and 5% O2. First, we determined the time course of changes in nuclear maturation and preimplantation developmental competence of in vitro-matured oocytes to estimate GVBD timing in high developmental competent oocytes. Two-thirds of oocytes that underwent GVBD in early IVM seemed to mainly contribute to the blastocyst yield. To confirm this result, we compared the preimplantation developmental competence of the early and late GVBD oocytes. Cleavage and blastocyst formation rates of early GVBD oocytes (80.2% and 52.7% under 20% O2, respectively, and 67.6% and 47.3% under 5% O2, respectively) were almost double those of late GVBD oocytes (44.8% and 26.0% under 20% O2, respectively, and 40.4% and 17.9% under 5% O2, respectively). With no observable alterations by checking the timing of GVBD in preimplantation developmental competence, oocyte evaluation based on GVBD timing can be used as an efficient and non-invasive preselection method for high developmental competent oocytes.
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Gupta, Swati, Sriti Pandey, Mehtab S. Parmar, Anjali Somal, Avishek Paul, Bibhudatta S. K. Panda, Irfan A. Bhat, et al. "Impact of oocyte-secreted factors on its developmental competence in buffalo." Zygote 25, no. 3 (June 2017): 313–20. http://dx.doi.org/10.1017/s0967199417000156.
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SummaryOocyte-secreted factors (OSFs) play an important role in the acquisition of oocyte developmental competence through bidirectional cross-talk between oocyte and cumulus cells via gap junctions. Thus, the present study was designed to investigate the effect of two OSFs, growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15), on the developmental competence of buffalo oocytes derived from two different follicle sizes. Cumulus–oocyte complexes (COCs) from large follicles (LF, >6 mm) or small follicles (SF, <6 mm) were collected and matured in vitro either in the presence of GDF9 or BMP15, or both, or with the denuded oocytes (DOs) as a source of native OSFs. Cleavage and blastocyst rates were significantly (P < 0.05) higher in LF-derived than SF-derived oocytes. Cleavage and blastocyst rates were significantly higher (P < 0.05) in the DOs and the combination groups compared with the control, GDF9 alone and BMP15 alone groups, both in LF-derived and SF-derived oocytes, although the cleavage and blastocyst rates did not differ significantly (P > 0.05) between DOs and combination groups. Relative mRNA analysis revealed significantly higher (P > 0.05) expression of the cumulus cell marker genes EGFR, HAS2, and CD44 in LF-derived than SF-derived oocyte; the expression of these markers was significantly higher (P > 0.05) in DOs and combination groups, irrespective of the follicle size. These results suggested that LF-derived oocytes have a higher developmental competence than SF-derived oocytes and that supplementation of GDF9 and BMP15 modulates the developmental competence of buffalo oocytes by increasing the relative abundance of cumulus-enabling factors and thereby increasing cleavage and the quality of blastocyst production.
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Brevini, T. A. L., R. Vassena, C. Francisci, and F. Gandolfi. "308MITOCHONDRIA RELOCATION, MICROTUBULE ASSEMBLING AND PARTHENOGENETIC DEVELOPMENTAL COMPETENCE OF PIG OOCYTES." Reproduction, Fertility and Development 16, no. 2 (2004): 273. http://dx.doi.org/10.1071/rdv16n1ab308.
Full textAbstract:
Developmental competence of in vitro-produced porcine embryos appears to be limited by specific maternally inherited cytoplasmic factors. We previously reported a relationship between mitochondria distribution during IVM, energy status, and oocyte developmental ability after parthenogenetic activation. The aim of the present study was to investigate the timing of mitochondria relocation during meiosis and the possible relationship with cytoskeleton organization in high and low competence oocytes. To this purpose, homogeneous groups of oocytes were matured in vitro (IVM) with 25% or 0% porcine follicular fluid (pff) to obtain different cytoplasmic competence (high and low, respectively) but similar nuclear maturation (Brevini et al., 2003, Theriogenology, 59, 440). After maturation, oocytes were parthenogenetically activated and cultured as previously described by Grupen et al., 2002 (Mol. Reprod. Dev., 62, 387–396). Active mitochondria were stained with MitoTracker® Orange CMTM Ros (Molecular Probes, Leiden, The Netherlands) at GV, MI and MII meiotic stages. At the same time microtubule organization was determined by immuno-cytochemistry using an antibody raised against α-tubulin (Sigma, St. Louis, MO, USA). Meiotic stages were assessed with DAPI. Specimens were examined with a Leica TCS-NT confocal microscope through an equatorial optical section. Nuclear maturation rate was comparable in the two groups at the end of IVM (46h). Mitochondria relocation from the periphery to the center of the oocyte was evident as early as 20h IVM in the 25% pff group (high competence), while 0% pff oocytes (low competence) did not show any mitochondria relocation at this time point. In agreement with the literature, α-tubulin was not detectable in GV oocytes, while at the end of IVM, α-tubulin was associated with the DNA, forming the meiotic spindle both in high and low competence oocytes. However, oocytes in the 25% pff group displayed a cytoplasmic microtubular organization that co-localized with mitochondria at 20 to 28h IVM. Conversely, α-tubulin was not detected in the cytoplasm of 0% pff oocytes at the same time points and 71% of these oocytes did not undergo any mitochondria relocation at all by the end of IVM. Altogether the present results show that mitochondria relocation takes place at a well-defined time during IVM and is temporally associated with the formation of the microtubule mesh in the oocyte cytoplasm. Low-developmental-competence oocytes display an altered mitochondria distribution and microtubule arrangement or seem to lack the temporal coupling of the two phenomena. We speculate that a tightly linked timing of mitochondria relocation and cytoskeleton microtubule formation in the cytoplasm of the oocyte during IVM may represent a key cytoplasmic factor regulating pig embryo parthenogenetic development.
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Yamazaki, Yukiko, Teruhiko Wakayama, and Ryuzo Yanagimachi. "Contribution of cumulus cells and serum to the maturation of oocyte cytoplasm as revealed by intracytoplasmic sperm injection (ICSI)." Zygote 9, no. 4 (November 2001): 277–82. http://dx.doi.org/10.1017/s0967199401001307.
Full textAbstract:
The fertilisability and developmental capacity of mouse oocytes matured in vitro were examined by in vitro fertilisation (IVF) and intracytoplasmic sperm injection (ICSI). While more than 50% of cumulus-enclosed oocytes were fertilised by IVF after maturation in serum-supplemented medium, none were fertilised when the oocytes matured without serum. By ICSI, the majority (78-94%) of the oocytes were fertilised regardless of the presence or absence of serum in oocyte maturation media. Although the majority (88-92%) of cumulus-free germinal vesicle oocytes underwent nuclear maturation in both serum-free and serum-containing media, those matured in the presence of serum were more readily fertilised by ICSI (43%) than those matured without it (3-5%). The cumulus-free oocytes co-cultured with cumulus cells but without serum were fertilised at 36%, suggesting some secreted factor promotes the oocyte's cytoplasmic maturation. The oocytes fertilised by ICSI developed into normal-term fetuses regardless of the presence or absence of serum or cumulus cells in oocyte maturation medium. These results lead us to conclude that (a) the cytoplasm of the oocytes can mature in serum-free medium and (b) the presence of both the serum and the cumulus cells in the medium surrounding maturing oocytes is beneficial for the development of the fertilisation- and development-competence of oocyte cytoplasm.
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Cavallari, Fernanda de Castro, Cláudia Lima Verde Leal, Roth Zvi, and Peter J. Hansen. "Effects of melatonin on production of reactive oxygen species and developmental competence of bovine oocytes exposed to heat shock and oxidative stress duringin vitromaturation." Zygote 27, no. 3 (June 2019): 180–86. http://dx.doi.org/10.1017/s0967199419000236.
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SummaryHeat shock may disrupt oocyte function by increasing the generation of reactive oxygen species (ROS). We evaluated the capacity of the antioxidant melatonin to protect oocytes using two models of oxidative stress – heat shock and the pro-oxidant menadione. Bovine cumulus–oocyte complexes (COC) were exposed in the presence or absence of 1 µM melatonin to the following treatments during maturation: 38.5°C, 41°C and 38.5°C+5 µM menadione. In the first experiment, COC were matured for 3 h with 5 µM CellROX® and analyzed by epifluorescence microscopy to quantify production of ROS. The intensity of ROS was greater for oocytes exposed to heat shock and menadione than for control oocytes. Melatonin reduced ROS intensity for heat-shocked oocytes and oocytes exposed to menadione, but not for control oocytes. In the second experiment, COC were matured for 22 h. After maturation, oocytes were fertilized and the embryos cultured for 7.5 days. The proportion of oocytes that cleaved after fertilization was lower for oocytes exposed to heat shock and menadione than for control oocytes. Melatonin increased cleavage for heat-shocked oocytes and oocytes exposed to menadione, but not for control oocytes. Melatonin tended to increase the developmental competence of embryos from heat-shocked oocytes but not for embryos from oocytes exposed to menadione or from control oocytes. In conclusion, melatonin reduced production of ROS of maturing oocytes and protected oocytes from deleterious effects of both stresses on competence of the oocyte to cleave after coincubation with sperm. These results suggest that excessive production of ROS compromises oocyte function.
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Li, Ruizhe, Yuzhu Luo, Jingtao Xu, Yonggang Sun, Zhijie Ma, and Shengmei Chen. "Effects of oxygen concentrations on developmental competence and transcriptomic profile of yak oocytes." Zygote 28, no. 6 (August 10, 2020): 459–69. http://dx.doi.org/10.1017/s0967199420000337.
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SummaryOxygen concentration influences oocyte quality and subsequent embryo development, but it remains unclear whether oxygen concentrations affect the developmental competence and transcriptomic profile of yak oocytes. In this study, we investigated the effects of different oxygen concentrations (5% versus 20%) on the developmental competence, reactive oxygen species (ROS) levels, glutathione (GSH) content, and transcriptomic profile of yak oocytes. The results showed that a low oxygen concentration significantly increased the maturation rate of yak oocytes (81.2 ± 2.2% vs 75.9 ± 1.3%) and the blastocyst quality of yak in vitro fertilized embryos. Analysis of ROS and GSH showed that a low oxygen concentration reduced ROS levels and increased the content of GSH (75.05 ± 7.1 ng/oocyte vs 50.63 ± 5.6 ng/oocyte). Furthermore, transcriptomic analysis identified 120 differentially expressed genes (DEGs) between the two groups of oocytes. Gene enrichment analysis of the DEGs indicated multiple cellular processes, including oxidative phosphorylation, transcription regulation, mitochondrial regulation, oestrogen signalling pathway, HIF-1 signalling pathway, TNF signalling pathway, were involved in the response to oxygen concentration alterations. Taken together, these results indicated that a low oxygen concentration improved the developmental competence of yak oocytes.
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Zhu, Cheng-Cheng, Yan-Jun Hou, Jun Han, Hong-Lin Liu, Xiang-Shun Cui, Nam-Hyung Kim, and Shao-Chen Sun. "Effect of Mycotoxin-Containing Diets on Epigenetic Modifications of Mouse Oocytes by Fluorescence Microscopy Analysis." Microscopy and Microanalysis 20, no. 4 (May 9, 2014): 1158–66. http://dx.doi.org/10.1017/s1431927614000919.
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AbstractMycotoxins, such as aflatoxin (AF), fumonisin B1, zearalenone (ZEA), and deoxynivalenol (DON), are commonly found in many food commodities. Mycotoxins have been shown to increase DNA methylation levels in a human intestinal cell line. We previously showed that the developmental competence of oocytes was affected in mice that had been fed a mycotoxin-containing diet. In this study, we explored possible mechanisms of low mouse oocyte developmental competence after mycotoxin treatment in an epigenetic modification perspective. Mycotoxin-contaminated maize (DON at 3,875μg/kg, ZEA at 1,897μg/kg, and AF at 806μg/kg) was included in diets at three different doses (mass percentage: 0, 15, and 30%) and fed to mice for 4 weeks. The fluorescence intensity analysis showed that the general DNA methylation levels increased in oocytes from high dose mycotoxin-fed mice. Mouse oocyte histone methylation was also altered. H3K9me3 and H4K20me3 level increased in oocytes from mycotoxin-fed mice, whereas H3K27me3 and H4K20me2 level decreased in oocytes from mycotoxin-fed mice. Thus, our results indicate that naturally occurring mycotoxins have effects on epigenetic modifications in mouse oocytes, which may be one of the reasons for reduced oocyte developmental competence.
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Maside, Carolina, Irene Sánchez-Ajofrín, Daniela Medina-Chávez, Benner Alves, José Julián Garde, and Ana Josefa Soler. "Oocyte Morphometric Assessment and Gene Expression Profiling of Oocytes and Cumulus Cells as Biomarkers of Oocyte Competence in Sheep." Animals 11, no. 10 (September 27, 2021): 2818. http://dx.doi.org/10.3390/ani11102818.
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Oocyte quality is crucial for subsequent embryo development and so it is a major challenge in assisted reproductive technologies. The aim of the present work was to evaluate the morphometric parameters of oocytes (experiment 1) and the relative gene expression of oocytes and cumulus cells (CCs) (experiment 2) as biomarkers of oocyte quality after individually culturing them (one oocyte or embryo/drop). In experiment 1, individually matured oocytes were measured and classified into small, intermediate, and large oocytes after a cluster analysis, based on total diameter (with zona pellucida, ZP), oocyte diameter (without ZP), and ZP thickness. These oocytes were individually fertilized in vitro and cultured. The embryo development was evaluated up to the blastocyst stage. According to the total diameter, oocyte diameter, and ZP thickness, the blastocyst rate decreased in the small oocytes group (3.1 ± 3.1, 14.1 ± 9.4, and 26.7 ± 3.9, respectively) compared to the intermediate (29.4 ± 5.2, 30.5 ± 10.1, and 28.6 ± 9.6, respectively) and large oocytes groups (54.2 ± 13.5, 44.4 ± 3.9, and 67.6 ± 12.4, respectively). In addition, the probability of reaching the blastocyst stage was positively related to the total diameter (p < 0.001), oocyte diameter (p < 0.05), and ZP thickness (p < 0.001). Furthermore, the relative gene expression of BAX, BCL2, GDF9, and GJA1 was lower in oocytes classified as large. In experiment 2, the mRNA transcript relative abundance pattern of genes in CCs was evaluated according to oocyte total diameter and developmental stage reached. CCs from oocytes classified as large and oocytes capable of developing to the blastocyst stage had a lower relative expression of BAX, STAR, and PTGS2, while a higher expression of HAS2 and SDC2 transcript was observed for those oocytes. In conclusion, oocyte morphometric parameters and gene expression analysis in oocytes and CCs provide methods for the identification of the most competent oocytes for assisted reproductive technologies in sheep.
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Preis, Kimberly A., George Seidel, and David K. Gardner. "Metabolic markers of developmental competence for in vitro-matured mouse oocytes." Reproduction 130, no. 4 (October 2005): 475–83. http://dx.doi.org/10.1530/rep.1.00831.
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In vitro maturation of oocytes has enormous potential in assisted reproductive technology, but its use has been limited due to insufficient knowledge of oocyte physiology during this dynamic period and lack of an adequate maturation system. The aim of this study was to characterize the metabolic profiles of three groups of oocytes throughout maturation: cumulus–oocyte complexes (COCs), denuded oocytes, and denuded oocytes co-cultured with cumulus cells. Mouse oocytes were collected from 28-day-old unstimulated females and matured in a defined medium. Oocytes were matured individually and transferred into fresh 0.5 μl drops of medium at 4 h intervals until 16 h. Ultramicrofluorimetry was used to quantitate carbohydrate consumption from and metabolite release into the medium. Glucose consumption and lactate production of COCs increased (P < 0.001) over the maturation interval (0–16 h). Glucose consumption by COCs that subsequently fertilized was higher between 8–12 h of maturation than by COCs that did not fertilize (38 versus 29 pmol/COC per h, respectively; P < 0.01). Lactate production by COCs that subsequently fertilized was higher between 8–16 h of maturation, than by oocytes that did not fertilize (8–12 h, 66 versus 46 pmol/COC per h, P < 0.01; 12–16 h, 56 versus 40 pmol/COC per h, respectively; P < 0.05). These data indicate that the final hours of maturation may hold a unique marker of oocyte competence, as during this time fertilizable COCs take up more glucose and produce more lactate than those not subsequently fertilized.
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Taketsuru, Hiroaki, Yuji Hirao, Naoki Takenouchi, Kosuke Iga, and Takashi Miyano. "Effect of androstenedione on the growth and meiotic competence of bovine oocytes from early antral follicles." Zygote 20, no. 4 (November 9, 2011): 407–15. http://dx.doi.org/10.1017/s0967199411000268.
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SummaryMedium that contains 17β-estradiol has been reported to support in vitro growth of bovine oocytes, isolated from early antral follicles, until the final stage. The aim of this study was to determine the effects of androstenedione in medium on such growing bovine oocytes. Oocyte–granulosa cell complexes were collected from early antral follicles and cultured for 14 days in medium supplemented with 17β-estradiol (0, 10 and 100 ng/ml) or androstenedione (0, 10 and 100 ng/ml). The mean diameter of oocytes measured after seeding on the culture substrate was 96.9 μm (n = 191). Either steroid was necessary for maintainance of the organization of oocyte–granulosa cell complexes over the 14-day culture period. In the 17β-estradiol- or the androstenedione-supplemented medium about 80% or 65%, respectively, of viable oocytes were recovered. In both groups the increase in oocyte size was significant after 14 days. The in vitro grown oocytes were cultured for a further 22–24 h for oocyte maturation; 13% and 30% of oocytes grown in the 10 and 100 ng/ml 17β-estradiol-supplemented medium reached metaphase II, respectively; more than 64% of oocytes grown in the androstenedione-supplemented medium matured to metaphase II. These results show that androstenedione, as 17β-estradiol, can maintain the viability of bovine oocyte–granulosa cell complexes and support the growth of oocytes, and that androstenedione promotes the acquisition of oocyte meiotic competence efficiently at a low dose.
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Ispada, J., T. A. Rodrigues, P. H. B. Risolia, R. S. Lima, D. R. Gonçalves, D. Rettori, M. Nichi, W. B. Feitosa, and F. F. Paula-Lopes. "Astaxanthin counteracts the effects of heat shock on the maturation of bovine oocytes." Reproduction, Fertility and Development 30, no. 9 (2018): 1169. http://dx.doi.org/10.1071/rd17271.
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The cellular mechanisms induced by elevated temperature on oocytes are not fully understood. However, there is evidence that some of the deleterious effects of heat shock are mediated by a heat-induced increase in reactive oxygen species (ROS). In this context, carotenoid antioxidants might have a thermoprotective effect. Therefore, the objective of this study was to determine the role of astaxanthin (AST) on oocyte ROS production and on the redox profile and developmental competency of cumulus-oocyte complexes (COCs) after 14 h heat shock (41°C) during in vitro maturation (IVM). Exposure of oocytes to heat shock during IVM increased ROS and reduced the ability of the oocyte to cleave and develop to the blastocyst stage. However, 12.5 and 25 nM astaxanthin rescued these negative effects of heat shock; astaxanthin counteracted the heat shock-induced increase in ROS and restored oocyte developmental competency. There was no effect of astaxanthin on maturation medium lipid peroxidation or on glutathione peroxidase and catalase activity in oocytes and cumulus cells. However, astaxanthin stimulated superoxide dismutase (SOD) activity in heat-shocked cumulus cells. In conclusion, direct heat shock reduced oocyte competence, which was restored by astaxanthin, possibly through regulation of ROS and SOD activity in oocytes and COCs.
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TORDA, Iuliu, Irina Ioana SPĂTARU, Gabriel OTAVĂ, Simona MARC, Oana BOLDURA, Ioan HUȚU, Bianca LUNGU, Beatrice TUDOR, Ovidiu GEORGESCU, and Călin MIRCU. "Quality Evaluation of Gilts and Sow’s Oocytes During In Vitro Maturation Based on Mitochondria Distribution." Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Veterinary Medicine 79, no. 1 (May 14, 2022): 26. http://dx.doi.org/10.15835/buasvmcn-vm:2021.0025.
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Mitochondria is the most frequently studied cell organelle in relation to development competence of the oocytes both in vivo and in vitro. Developmental competence of oocyte is crucial for embryonic development, the molecular activity until the activation of the embryonic genome being based on the maternal reserves stored in the oocyte. Study was designed to qualitatively evaluate 133 COC class C1 and class C2 gilts and sow’s oocytes according to the distribution of mitochondria after IVM, based on Rhodamine 123 stain solution. Regarding mitochondrial distribution, the percentage of oocytes that had a homogeneous distribution around the germinal vesicle was higher in group C1 than C2 and also higher in sow oocytes than in gilts oocytes. For class 1, the difference was 10.58% in favor of sows, the same trend is maintained for C2, the difference being 4.37%. The results are confirmed by morphological examination, where C1 sow’s oocytes matured 26.09% more, compared to gilts oocytes, a difference maintained for C2 oocytes, being 27.4% more sow’s oocytes IVM compared to gilts. Based on mitochondrial distribution we observed that the stage of sexual development of females influences the IVM of oocytes. For pig’s IVF it’s recommended to use C1 sow oocytes.
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Cavalera, Federica, Milena Simovic, Mario Zanoni, Valeria Merico, Silvia Garagna, and Maurizio Zuccotti. "IVM of mouse fully grown germinal vesicle oocytes upon a feeder layer of selected cumulus cells enhances their developmental competence." Reproduction, Fertility and Development 31, no. 6 (2019): 1068. http://dx.doi.org/10.1071/rd18444.
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In the ovary, acquisition of oocyte developmental competence depends on a bidirectional exchange between the gamete and its companion cumulus cells (CCs). In this study we investigated the contribution of CCs surrounding oocytes of known developmental competence or incompetence to the acquisition of oocyte developmental competence. To this end, feeder layers of CCs (FL-CCs) were prepared using CCs isolated either from: (1) developmentally competent mouse oocytes whose nucleolus was surrounded by a chromatin ring (FL-SN-CCs); or (2) developmentally incompetent mouse oocytes whose nucleolus was not surrounded by a chromatin ring (FL-NSN-CCs). Denuded, fully grown oocytes (DOs) were matured to the MII stage on either FL-SN-CCs or FL-NSN-CCs, inseminated with spermatozoa and cultured throughout preimplantation development. FL-SN-CCs significantly improved the acquisition of oocyte developmental competence, with a blastocyst development rate equal to that for maturation of intact cumulus–oocyte–complexes. In contrast, DOs matured on FL-NSN-CCs or in the absence of CCs exhibited developmental failure, with embryos arresting at either the 4-cell or morula stage. These results set a culture platform to further improve the protocols for the maturation of DOs and to unravel the molecules involved in the cross-talk between the gamete and its companion CCs during the germinal vesicle to MII transition.
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Biase, Fernando Henrique, Lúcia Martelli, Giovana Krempel Fonseca Merighe, Weruska Karyna Freitas Santos Biase, Moyses Miranda, Lawrence Charles Smith, and Flávio Vieira Meirelles. "A retrospective model of oocyte competence: global mRNA and housekeeping transcripts are not associated with in vitro developmental outcome." Zygote 17, no. 4 (April 27, 2009): 289–95. http://dx.doi.org/10.1017/s0967199409005395.
Full textAbstract:
SummaryOocyte developmental competence depends on maternal stores that support development throughout a transcriptionally silent period during early embryogenesis. Previous attempts to investigate transcripts associated with oocyte competence have relied on prospective models, which are mostly based on morphological criteria. Using a retrospective model, we quantitatively compared mRNA among oocytes with different embryo development competence. A cytoplasm biopsy was removed from in vitro matured oocytes to perform comparative analysis of amounts of global polyadenylated (polyA) mRNA and housekeeping gene transcripts. After parthenogenetic activation of biopsied oocytes, presumptive zygotes were cultured individually in vitro and oocytes were classified according to embryo development: (i) blocked before the 8-cell stage; (ii) blocked between the 8-cell and morulae stages; or (iii) developed to the blastocyst stage. Sham-manipulated controls confirmed that biopsies did not alter development outcome. Total polyA mRNA amounts correlate with oocyte diameter but not with the ability to develop to the 8-cell and blastocyst stages. The last was also confirmed by relative quantification of GAPDH, H2A and Hprt1 transcripts. In conclusion, we describe a novel retrospective model to identify putative markers of development competence in single oocytes and demonstrate that global mRNA amounts at the metaphase II stage do not correlate with embryo development in vitro.
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Kang, J. K., J. H. Yang, K. Naruse, C. S. Park, K. S. Min, and D. I. Jin. "315THE REDUCTION OF MATURATIONAL COMPETENCE BY STREPTOMYCIN DURING IN VITRO MATURATION OF GOAT FOLLICULAR OOCYTES." Reproduction, Fertility and Development 16, no. 2 (2004): 277. http://dx.doi.org/10.1071/rdv16n1ab315.
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Antibiotics are commonly added to mammalian oocyte maturation media, but their effects on oocytes maturation have not been examined thoroughly. Goat follicular oocytes were used to investigate whether penicillin, streptomycin or gentamycin affect maturational competence of oocytes and subsequent parthenogenetic activation potential in vitro. Cumulus-oocyte complexes collected from a local abattoir were matured for 24h in five treatments, and matured oocytes were cultured for 48h in five treatments after parthenogenetic activation by treatment with ionomycin, followed by immediate exposure to 6-diethlaminopurine; (1) Control: TCM-199 medium with no antibiotics, (2) TCM-199 with 100IU/mL−1 penicillin (P-4687, Sigma, St. Louis, MO, USA), (3) TCM-199 with 50μgmL−1 streptomycin (S-1277, Sigma), (4) TCM-199 with 50μgmL−1 gentamycin (G-1264, Sigma) and (5) TCM-199 with both 100IUmL−1 penicillin and 50μgmL−1 streptomycin. Maturation rates at 24h post-in vitro maturation and parthenogenetic cleavage development at 48h post-activation were evaluated. Data were analyzed by ANOVA and Student’s t-test. Penicillin and gentamicin treatment groups did not affect maturation rates and percentages of cleavage to 2–4 cell stage at 48h post-chemical oocyte activation. However, when streptomycin was present in the maturation medium, the percentages of matured oocytes at 24h post-in vitro maturation of immature goat oocytes were significantly lower than those from the other groups. However, among the five treatments, there was no significant difference in cleavage rates of matured oocytes at 48h post-activation (Table 1). Therefore, streptomycin did interfere with the maturation of immature goat oocytes, but did not affect the subsequent development of matured goat oocytes. The mechanism by which streptomycin affects the maturation of goat follicular oocytes needs to be investigated further. We conclude that streptomycin in oocyte maturation medium can be detrimental during in vitro maturation of goat follicular oocytes. Table 1 Effect of antibiotics on maturational competence of goat follicular oocytes and subsequent parthenogenetic activation potential in vitro
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Herrick, J. R. "262 ISOBUTYLMETHYLXANTHINE REVERSIBLY SUPPRESSES SPONTANEOUS AND EQUINE CHORIONIC GONADOTROPIN/EPIDERMAL GROWTH FACTOR-STIMULATED MEIOSIS IN FELINE OOCYTES." Reproduction, Fertility and Development 23, no. 1 (2011): 229. http://dx.doi.org/10.1071/rdv23n1ab262.
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Recent studies have shown that short-term exposure to phosphodiesterase inhibitors (decreased cAMP degradation) or adenylate cyclase stimulators (increased cAMP synthesis) inhibits spontaneous oocyte maturation and improves the developmental competence of oocytes after gonadotropin-induced maturation. A similar approach may improve the developmental competence of in vitro matured feline oocytes. The objectives of this study were to 1) determine if a nonspecific phosphodiesterase inhibitor [isobutylmethylxanthine (IBMX); 100 μM] or an adenylate cyclase stimulator (forskolin; 100 μM) would suppress spontaneous or eCG (1 IU mL–1)/epidermal growth factor (EGF; 25 ng mL–1)-induced maturation of feline oocytes in vitro; 2) evaluate the reversibility of chemically induced meiotic arrest; and 3) assess the developmental competence of meiotically arrested oocytes. Cumulus–oocyte complexes were cultured in modified feline optimized culture medium [6 mM glucose, 0.1 mM cysteamine, 0.6 mM cysteine, 0.5× minimal essential medium (MEM) essential amino acids, 1× MEM vitamins, and 1× insulin-transferrin-selenium; Herrick et al. 2010 Biol. Reprod. 82, 552–562] supplemented with (+) or without (–) IBMX, forskolin, or eCG/EGF (eE). The IBMX decreased (P < 0.05; mixed model ANOVA) the incidence of spontaneous maturation (–eE) after 24 h of culture (84.6%, germinal vesicle, GV; 6.7% metaphase II, MII) compared with control (no supplements) oocytes (18.8% GV, 42.0% MII). Forskolin (–eE) stimulated (P < 0.05) meiosis (6.1% GV, 81.7% MII), so it was not tested in subsequent experiments. The IBMX also inhibited (P < 0.05) eE-induced meiosis compared with control (–IBMX +eE) oocytes after 18 h (87.6 v. 27.1% GV, 2.5 v. 11.0% MII), 24 h (68.0 v. 11.9% GV, 5.6 v. 66.1% MII), and 30 h (58.1 v. 9.4% GV, 14.6 v. 64.4% MII) of culture. To evaluate the reversibility of IBMX, oocytes were cultured +IBMX –eE for 12 h and then transferred to medium –IBMX +eE. After 12 h of culture –IBMX +eE (24 h total), fewer (P < 0.05) IBMX-exposed oocytes were MII (6.6%) compared with control oocytes cultured for 24 h +eE –IBMX (70.2%). The proportion of IBMX-exposed oocytes reaching MII increased (P < 0.05) following 18 h of culture –IBMX +eE (30 h total; 49.4% MII), and by 24 h of culture –IBMX +eE (36 h total; 66.1% MII) was similar (P > 0.05) to the proportion of MII oocytes (78.3%) that had been cultured continuously for 36 h –IBMX +eE. Finally, oocytes were cultured for 0 h or 12 h +IBMX –eE followed by 24 h of culture –IBMX +eE, coincubated with frozen–thawed spermatozoa (5 × 105 sperm mL–1, 22 h), and the resulting embryos cultured (6% CO2, 5% O2) until day 7 post-insemination (Herrick et al. 2007 Biol. Reprod. 76, 858–870). The proportion of oocytes cleaving (83.0 v. 79.9%) and the proportions of oocytes (20.8 v. 18.7%) or embryos (25.2 v. 23.6%) developing to the blastocyst stage were not affected (P > 0.05) by 12 h of IBMX exposure during oocyte maturation. These results demonstrate that IBMX reversibly inhibits both spontaneous and eCG/EGF-induced meiosis in feline oocytes without compromising the oocyte’s developmental competence. This work was supported by the College of Veterinary Medicine’s Companion Animal Memorial Fund at the University of Illinois.
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Deb, G. K., S. R. Dey, J. I. Bang, and I. K. Kong. "192 9-cis-RETINOIC ACID AFFECTS OOCYTE COMPETENCE MARKER GENE EXPRESSION IN THE BOVINE IN VITRO-MATURED OOCYTES AND CUMULUS CELLS." Reproduction, Fertility and Development 24, no. 1 (2012): 208. http://dx.doi.org/10.1071/rdv24n1ab192.
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Oocyte competence is the ability of an oocyte to undergo pre- and post-implantation development and to deliver a healthy offspring. A close association between the oocyte and the cumulus cells (CC) affects oocyte competence. Expression of several genes in the CC, known as oocyte competence markers, correlates with subsequent embryo development and quality. Addition of 9-cis-retinoic acid (9cisRA) to maturation medium increases oocyte competence through multiple mechanisms, including FSH/LH receptor expression, polyadenylation, growth factors signaling, oxidative-stress protection, or decreasing oocyte TNF-α gene expression. However, the effect of 9cisRA on the expression of oocyte competence markers in the oocytes and CC has not been determined. Therefore, the present study evaluated the effect of 9cisRA on the expression of oocyte competence marker genes in the oocytes and in the CC. Bovine cumulus–oocyte complexes, isolated from ovaries collected at the abattoir, were matured in vitro in the presence of 0 or 5 nM 9cisRA in the maturation medium (TCM-199 supplemented with 10% fetal bovine serum, 1 μg mL–1 of β-oestradiol, 10 μg mL–1 of follicle stimulating hormone, 0.6 mM cystein and 0.2 mM Na-pyruvate). After maturation, expression of target transcripts was quantified in CC and zona-free oocytes by SYBER green real-time PCR. The expression was normalized against a minimum of 2 out of 4 reference genes analyzed each time with target genes. The best combination of reference genes was automatically calculated by the CFX manager V1.1 program (BioRad) based on M-value during the analysis of gene expression data. A minimum of 5 biological replicates (50–60 oocytes/replicate) were performed for statistical analysis using a Student's t-test. Results indicated that 9cisRA increased (P < 0.05 to P < 0.001) expression of gremlin 1, prostaglandin G/H synthase 2, pentraxin 3, midkine, CD9 and thioredoxin mRNA in oocytes (3.0-, 2.8-, 3.1-, 2.0-, 4.0- and 2.4-fold) and CC (4.0-, 3.2-, 1.9-, 1.7-, 4.0- and 2.4-fold) compared to controls. In contrast, the aldose reductase 1b1 mRNA was down-regulated both in oocytes (1.0- vs 2.0-fold; P < 0.05) and in CC (1.0- vs 1.9-fold; P < 0.04) compared to the respective controls. In conclusion, the present study indicates that 9cisRA influences mRNA expression of oocytes and cumulus cells. This might be another explanation of the improved embryo development and quality in response to 9cisRA during in vitro maturation. This work was partly supported by a scholarship from the BK21 program, the KRF (KRF-2008-211-F00011), the Next-generation BioGreen 21 Program (No. PJ007990012011), IPET (110020-3 and 109016-3) and the KOSEF (10525010001-05N2501-00110).
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Lee, Ju Hee, Jae Kyun Park, Sook Young Yoon, Eun A. Park, Jin Hyun Jun, Hyunjung J. Lim, Jayeon Kim, and Haengseok Song. "Advanced Maternal Age Deteriorates the Developmental Competence of Vitrified Oocytes in Mice." Cells 10, no. 6 (June 21, 2021): 1563. http://dx.doi.org/10.3390/cells10061563.
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Advanced maternal age (AMA) is known to be related to the decrease in the quality and quantity of oocytes. Oocyte vitrification is now considered an established assisted reproductive technology for fertility preservation. However, it remains unclear whether the oocytes in older women are more sensitive to various insults during vitrification. Thus, we evaluated whether AMA affects cellular and molecular features and developmental outcomes of oocytes after vitrification in mice. The oocytes were grouped as young fresh (YF), young vitrified/warmed (YV), aged fresh (AF), and aged vitrified/warmed (AV). The survival rate of AV oocytes was significantly lower than that of YV oocytes. The rates of fertilization, cleavage, and blastocyst formation of AV oocytes were significantly lower than those of other groups. AV oocytes were represented as aberrations in mitochondria distribution, microvacuole size, and autophagosome formation, leading to delayed embryo development in mice. This delay was associated with a reduced number of total cells and trophectoderm in the blastocyst developed from AV oocytes. Collectively, AMA exaggerates the vulnerability of oocytes to cryo-damage that occurs during vitrification in mice, suggesting that the current vitrification protocols optimized for oocytes from young females should be modified for oocytes from aged women.
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Lan, Tianyang, Kang Zhang, Feifei Lin, Qifu He, Shenghui Wu, Zhiming Xu, Yong Zhang, and Fusheng Quan. "Effects of MICU1-Mediated Mitochondrial Calcium Uptake on Energy Metabolism and Quality of Vitrified-Thawed Mouse Metaphase II Oocytes." International Journal of Molecular Sciences 23, no. 15 (August 3, 2022): 8629. http://dx.doi.org/10.3390/ijms23158629.
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Background: Oocyte vitrification has been widely used in the treatment of infertility and fertility preservation. However, vitrification-induced mitochondrial damage adversely affects oocyte development. Several studies have reported that mitochondrial calcium uptake protein 1 (MICU1) regulates the uptake of mitochondrial calcium by the mitochondrial calcium uniporter (MCU) and subsequently controls aerobic metabolism and oxidative stress in mitochondria, but research considering oocytes remains unreported. We evaluated whether the addition of MICU1 modulators enhances mitochondrial activity, pyruvate metabolism, and developmental competence after warming of MII oocytes. Methods: Retrieved MII oocytes of mice were classified as vitrified or control groups. After thawing, oocytes of vitrified group were cultured with or without DS16570511 (MICU1 inhibitor) and MCU-i4 (MICU1 activator) for 2 h. Results: Mitochondrial Ca2+ concentration, pyruvate dephosphorylation level, and MICU1 expression of MII oocytes were significantly increased after vitrification. These phenomena were further exacerbated by the addition of MCU-i4 and reversed by the addition of DS16570511 after warming. However, the mitochondrial membrane potential (MMP) and adenosine triphosphate (ATP) in vitrified-warmed MII oocytes drop significantly after vitrification, which was improved after MCU-i4 treatment and decreased significantly after DS16570511 treatment. The vitrification process was able to elicit a development competence reduction. After parthenogenetic activation, incubation of the thawed oocytes with MCU-i4 did not alter the cleavage and blastocyst rates. Moreover, incubation of the thawed oocytes with DS16570511 reduced the cleavage and blastocyst rates. Conclusions: MICU1-mediated increasing mitochondrial calcium uptake after vitrification of the MII oocytes promoted the pyruvate oxidation, and this process may maintain oocyte development competence by compensating for the consumption of ATP under stress state.
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Catandi, G., J. Stokes, L. Maclellan, C. Broeckling, and E. Carnevale. "141 Diet supplementation alters oocyte lipid content and developmental competence in mares." Reproduction, Fertility and Development 33, no. 2 (2021): 178. http://dx.doi.org/10.1071/rdv33n2ab141.
Full textAbstract:
The equine oocyte is dense in lipids, which may serve as an energy source for oocyte maturation and later embryonic development. However, the association between lipid content and fertility remains to be determined, as does the extent that diet can modify oocyte lipids. We hypothesised that diet supplementation can alter the oocyte lipid profile and subsequent developmental potential. In Study 1, we examined if oocyte triglyceride (TG) relative abundance was affected by dietary supplementation. Mares (16–22 years, n=9) were fed grass/alfalfa hay and supplemented daily with a combination of commercially available feed additives designed to promote equine wellness and fertility [Equine GI™ (147g daily), Potency® (28g daily), Motility Plus® (23g daily), Healthy Weight Oil (60mL daily), Platinum Performance Inc.]. Oocytes were collected from the mares before (PRE) and after ≥8 weeks (POST) of supplementation during the natural breeding season. In Study 2, we compared oocyte developmental potential after injection of sperm into oocytes obtained from mares supplemented for ≥8 weeks with the same additives (ADD, 18–24 yr, n=5) or from a similar group of mares supplemented with a grain control diet (450g of grain mix and 60ml of corn oil daily, GRN, 19–23 years, n=5). Oocytes were collected from dominant follicles (≥35mm) during oestrus and at 20±2 h after induction of follicular maturation. In Study 1, oocytes were denuded of cumulus cells after collection, snap frozen, and assessed for TG composition by nontargeted liquid chromatography-mass spectrometry using an Acquity UPLC system (Waters). In Study 2, recovered oocytes were placed in maturation medium for 22±2h before being injected with sperm from one stallion, and blastocyst formation was assessed in 7 or 8 days. A total of 100 annotated TG species were identified. Normalized peak areas for PRE and POST oocyte TG were compared using two-tailed, paired t-tests. Blastocyst development rates were compared by Fisher’s exact test. Relative abundance of 71 TG species differed (P ≤ 0.05) between PRE and POST; all TG species as well as total relative abundance of TG were higher in oocytes from PRE compared with POST. Blastocyst rates per sperm-injected oocyte were greater (P=0.03) for ADD (40%, 6/15) than for GRN (5%, 1/19). Dietary supplementation of the complex mix of nutrients to middle-aged and older mares resulted in reduced relative abundance of TG in oocytes and improved developmental potential. We determined that oocyte lipid content can be modified through diet. The extent that diet supplementation improved oocyte competence by altering the lipid profile is still to be determined.