Dissertations / Theses on the topic 'Oocytes competence'
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Christmann, Leandro. "Acquisition of meiotic competence in growing porcine oocytes." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339451.
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Zhu, Jie. "Pig oocyte activation and developmental competence of parthenogenetically activated oocytes : in vitro and in vivo studies." Thesis, University of Edinburgh, 2001. http://hdl.handle.net/1842/27741.
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In somatic cell nuclear transfer in mammals, to clone a piglet is still a big challenge. Although many factors could contribute to the low success rate, such as quality of donor and recipient cells, types of donor cell including sources of animal breeds and tissues, number of passages and culture conditions, timing of cell cycle, procedures of nuclear transfer, techniques and embryos transfer, one of the factors is believed to be poor oocyte activation, especially in pig nuclear transfer. Therefore studies presented in this thesis aimed at the establishment of an in vitro culture system for pig oocyte maturation and embryo culture, based on this system an electrical activation protocol for pig oocytes was optimized and also tested by monitoring in vivo development of activated pig oocytes. Finally, the protocol was used for activating pig embryos reconstructed by transfer of somatic cells into enucleated ovulated oocytes and for production of pig parthenotes to maintain pregnancies of cloned pig embryos, which resulted in the birth of a cloned male piglet. The thesis comprises a total of 6 chapters. In addition to the review of literature (Chapter 1), general materials and methods (Chapter 2) and general discussion (Chapter 6), in Chapter 3 and 4, the studies focused on optimizing electrical parameters on pig oocyte activation and investigating the effects of activation conditions including temperature, activation medium, and concentrations of Ca2+ and Mg2+ in activation medium and diploidization of activated oocytes. These experiments were carried out in vitro, whereas experiments in Chapter 5 were conducted in vivo to assess the in vivo developmental competence of in vitro matured (IVM) pig oocytes activated by the improved activation protocol.
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Zarate-Garcia, Larissa. "Understanding the meiotic competence of oocytes derived from oogonial stem cells." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/413809/.
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This thesis investigates whether Oogonial Stem Cells (OSCs) exist and can be isolated from the adult mouse ovary. It also examines their ability to differentiate into oocyte-like cells in vitro. Transmembrane domains in the DEAD-box polypeptide 4 (DDX4) – the germline marker used in this antibody-based isolation – are examined using in silico protein modelling. The specificity of this antibody to DDX4 is tested in male and female germline cells. It is shown that the DDX4 antibody may have some specificity for DDX4, but the existence of a surface-bound DDX4 is unlikely. OSC-like cells can be isolated from the ovary using the DDX4 antibody by Fluorescence-Activated Cell Sorting (FACS). However, gene expression analysis and protein immunofluorescence show that these cells do not initially express DDX4 or possess germline identity. Despite this, they acquire some pre-meiotic and oocyte-specific markers in culture, including DDX4. Critically, the cells never express meiosis-specific markers even in the presence of meiotic enhancers BMP4 and retinoic acid. It is unlikely that these ovarian cells are being sorted by means of a cell surface DDX4 expression, because another antibody to a larger DDX4 epitope fails to detect DDX4 in isolated cells. These findings highlight that freshly isolated OSCs are not germ stem cells, and are not being isolated by their DDX4 expression, but instead may reflect an artefact of the antibody used or procedure adopted. Altogether this work offers support to the established dogma that the adult ovary is populated at birth by a fixed number of oocytes, and that adult de novo production is a rare or insignificant event.
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Koeman, Jennifer. "Developmental competence of prepubertal and adult goat oocytes cultured in semi-defined media." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33417.
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In vitro production of embryos from oocytes recovered by laparoscopic oocyte pick-up (LOPU) offers great potential for the propagation of genetically valuable animals. In turn, the application of these techniques to prepubertal animals presents added benefits in that prepubertal animals may supply a greater number of oocytes than adult animals. The aim of the present study was to evaluate the developmental competence of prepubertal and adult goat oocytes cultured in semi-defined media. The follicular response and recovery of oocytes via LOPU from hormonally stimulated prepubertal and adult goats were also assessed.Oocytes were collected over a 15-wk period from prepubertal goats, ranging in age between 3--7 mo, and adult controls, ranging in age between 2--4 yr, randomly divided into 10 collection groups. Oocytes from six of the ten collections were matured for 26 h. Four collections were not completed due to technical difficulties. Following insemination, zygotes were cultured for 4 d in G1.2 followed by 4 d in G2.2. Morulae and blastocysts were scored via light microscopy on Days 7 and 9, followed by fluorescent staining on Day 9 for cell counts. (Abstract shortened by UMI.)
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Demond, Hannah [Verfasser], and Bernhard [Akademischer Betreuer] Horsthemke. "Effects of preovulatory aging on the developmental competence of mouse oocytes / Hannah Demond. Betreuer: Bernhard Horsthemke." Duisburg, 2016. http://d-nb.info/1102896969/34.
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Held, Eva [Verfasser]. "Morphological reflectors and molecular predictors of preimplantation developmental competence of bovine oocytes and embryos / Eva Held." Bonn : Universitäts- und Landesbibliothek Bonn, 2013. http://d-nb.info/1043056831/34.
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Silva, Celia Costa Gomes da. "Effects of inhibin, activin and follistatin on the developmental competence of in vitro matured bovine oocytes." Thesis, University of Reading, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266146.
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CONSIGLIO, A. LANGE. "Equine compact cumulus oocytes for in vitro reproductive technologies : meiotic competence improvement and relationship with nutritional status and puberal development." Doctoral thesis, Università degli Studi di Milano, 2008. http://hdl.handle.net/2434/54758.
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The aim of this thesis was to investigate cellular processes critical to equine maturation, fertilization and embryo development in vitro.
Equine compact cumulus oocytes (CCO) in vitro have low competence, so we evaluated the efficacy of a pre-maturation step in improving the coordination of cytoplasmic and nuclear maturation of CCO by the addition of Roscovitine and our results showed partial improving of the competence of these oocytes.
Moreover, we carried out a study to examine the immunolocalization of leptin (Ob) and leptin receptor (Ob-R) in CCO recovered from fillies and from mares of light vs heavy body weight breeds after slaughtering and to further improve the maturation rate of CCO we supplemented the maturation medium with leptin and investigated its effect in expanded and compact cumulus oocytes on maturation, fertilization and embryo cleavage rates after intra cytoplasmic sperm injection (ICSI). The results supported the hypothesis that, in the horse, leptin is differently localized during oocyte IVM showing different immunoreaction intensity related either to the horse breed or to the reproductive puberal development. In vitro, the presence of leptin during oocyte maturation improves the progression of meiosis and the rate of fertilization after ICSI but, by contrast to other species, in our horse model no differences were detected in the subsequent development rates of embryos: probably species-differences exist in embryos with regard to sensitivity to leptin.
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GARCIA, BARROS RODRIGO. "DEVELOPMENT OF NEW OOCYTE IN VITRO CULTURE STRATEGIES TO ENHANCE THE OUTCOME OF ASSISTED REPRODUCTIVE TECHNOLOGIES." Doctoral thesis, Università degli Studi di Milano, 2021. http://hdl.handle.net/2434/809746.
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Fertility preservation has received unprecedented attention nowadays. In addition to cryopreservation and re-implantation of embryos, oocytes, and ovarian tissue pieces, in vitro culture system for follicles/oocytes has been considered an alternative strategy for fertility preservation. Reproduction strategies based on the recovery of oocytes' population from antral follicles are unsatisfactory, and the success of this approach has not exceeded 35% of embryos produced in vitro for over 30 years. The possibility of accessing the reserve of smaller follicles (primordial, secondary, and up to the preantral stage) would amplify the number of gametes available for increasing reproductive potential. Furthermore, this would open enormous prospects for the rescue of fertility in various conditions in the human clinic and genetic rescue in animal breeding and biodiversity preservation programs. However, this would require developing protocols capable of growing immature oocytes to the stage in which they can be matured and fertilized in vitro.
Culture systems to achieve in vitro growth (IVG) of immature oocytes to maturity and subsequent fertilization in vitro (IVF) have been the subject of research for almost 40 years. Several systems that support the growth of later stages of follicle development from rodents have been developed, with some reporting the production of live young, but they are still at an experimental stage, and further research is required before the protocols could be clinically applied.
One of the significant limitations is identifying growth factors, hormones, and nutrients necessary for each specific follicle development stage. This evidence has led to hypothesize the development of culture systems consisting of a step-by-step approach, although no reliable protocols have been developed so far. The oocyte culture at the early stages of development represents an alternative to maximize the potential source of gamete used for fertility preservation. Several attempts have been made to recreate these conditions in vitro, but no reliable protocols have been developed to date. The lack of knowledge in the mechanisms involved in the early development of the oocyte and this passage from growing to fully grown stage be one of the most critical steps during oocyte development, these still represent the significant limiting factor for this technology.
The studies conducted during the doctorate program led to defining a physiological culture system that successfully differentiated growing bovine oocytes. This study used parameters predictive of oocyte differentiation to evaluate the current technique's efficiency and efficacy.
Based on previous observations from our laboratory, we initially hypothesized that zinc plays a role during the latest stages of oocyte growth and differentiation, particularly in controlling transcription during the final stage of oocyte growth. This first study demonstrated that zinc supplementation improves the meiotic competence of growing oocytes, affects the global transcription activity and the global DNA methylation. This information was used in the next part to better define a culture system for growing oocytes.
The subsequent study provided a 5-days protocol named L-IVCO (long in vitro culture of oocytes) to promote growing oocyte differentiation until the acquisition of meiotic and embryonic developmental competencies in a significantly higher proportion of the published protocols. This study demonstrated that a physiological medium could support a gradual transition of the oocyte from immature to mature stage, thus generating suitably quality blastocysts after fertilization.
In conclusion, our studies provide an improved protocol that can increase the source of fertilizable gametes in preservation programs and gives a prospective approach in human clinics, animal breeding programs, and salvage intervention of threatened species. Moreover, our studies defined a model to perform in-depth studies of the cellular and molecular processes that regulate the acquisition of meiotic and developmental competence during oocyte differentiation.
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Assidi, Mourad. "Oocyte competence and cumulus cells gene expression." Thesis, Université Laval, 2010. http://www.theses.ulaval.ca/2010/27679/27679.pdf.
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Yang, Min. "Evaluation of Oocyte Developmental Competence and Potential Strategies to Improve Oocyte Quality." DigitalCommons@USU, 2018. https://digitalcommons.usu.edu/etd/6914.
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Assisted reproductive technologies (ARTs) have now been extensively used to promote reproductive efficiency as a fertility treatment not only in human medicine but also animal reproduction. ARTs serve as an important tool to advance the fundamental knowledge of reproductive processes. The quality of female’s eggs defines its ability to undergo maturation, fertilization, and development. This quality is determined by various factors and is crucial for the success of ARTs. Any alternations happening during the egg growth and maturation process can result in the decreased quality, which could have long-lasting effects on development. Improving the developmental efficiency of the egg is quite challenging due to the limited knowledge on the underlying mechanism of how the egg regulates biological processes during the growth and maturation phase. We compared good-quality and poor-quality eggs to detect the key players in determining the egg quality at the molecular level. Our finding also provides information that benefits the understanding of how the nutrients in culture medium facilitate oocyte maturation, which will eventually help optimize the condition for oocyte culture. Based on the results from these comparative studies, we proposed a potential strategy for improving egg quality. The knowledge obtained from our research offers promise for many applications in the treatment of infertility and improvement of ART efficiency.
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Roura, Llerda Montserrat. "Fatty acids goat follicular fluid: effect on oocyte competence." Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/399336.
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Els àcids grassos (AAGG) són una important font d’energia pels oòcits en fase de creixement. Per tant, l’estudi del fluid fol·licular (FF) on aquests oòcits maduren és d’especial interès. En estudis previs, Romaguera i col. (2011) va concloure que els oòcits de fol·licles grans (≥ 3mm) eren més competents que els de fol·licles petits. A més, Catalá i col. (2015) van demostrar que hi havia una producció diferencial d’embrions entre les estacions de l’any, sent significativament més baixes a la tardor que a l’hivern.
La nostra hipòtesi va ser que el perfil d’AAGG de cabres adultes i prepúbers, així com de diferents mides de fol·licle i de diferents estacions de l’any, ens podria donar informació per poder-ho relacionar amb la competència oocitària. El nostre objectiu va ser determinar si es podria fer servir aquest perfil com a marcador molecular per la qualitat oocitària.
En l’experiment 1, vàrem analitzar el perfil d’AAGG en FF de cabres adultes i prepúbers, segons edat, mida del fol·licle i època de l’any. Entre d’altres, vàrem trobar diferències en el total d’AAGG poliinsaturats (PUFA), la ràtio n6:n3 segons edat de la femella i mida de fol·licle i per estacions de l’any.
En l’experiment 2, vàrem avaluar la competència de l’oòcit provinent de femelles prepúbers afegint diferents ràtios dels àcids linoleic (LA: n6 PUFA) i α-linolenic (ALA: n3 PUFA) en el medi de MIV. Vàrem observar que la ràtio LA:ALA 200:50 µM tenia un efecte perjudicial sobre el desenvolupament embrionari dels oòcits quan es comparava amb els grups control i la resta dels tractaments (100:50 i 50:50 µM), quan els oòcits eren fecundats in vitro (FIV) (2.63 % vs ≈ 13 %) però no quan eren activats partenogenèticament.
L’experiment 3 consistia en l’estudi de l’efecte de les diferents ràtios de LA:ALA en l’oòcit de cabra prepúber avaluant l’activitat i distribució mitocondrial, la concentració d’ATP i l’expressió gènica relativa. Vàrem observar que hi havia un canvi si es comparava els oòcits en el moment de recol·lecció i després de 24h de MIV en l’activitat mitocondrial, en la distribució d’aquests orgànuls i en la producció d’ATP. A més, en el grup de 200:50 µM l’activitat mitocondrial era més alta que en la resta de grups. Es van analitzar l’expressió relativa de 9 gens que es troben alterats si la cèl·lula pateix estrès, comprometent la seva viabilitat. D’entre aquests gens, es varen trobar diferències d’expressió entre les 0 i 24h de maduració pels gens: GPX1, RPL19 i SOD1, però no entre els diferents tractaments.
En conclusió, es va trobar que el perfil d’AAGG de FF de cabra és similar a la del fluid fol·licular de vaques, ovelles i dona. Les principals diferències trobades en les cabres es devien principalment a l'edat de la femella. Es va trobar una relació directa entre la ràtio n6:n3 present en el FF segons mida del fol·licle i estació de l’any amb resultats previs en el nostre laboratori en la producció in vitro d’embrions, suggerint que aquesta ràtio podria ser un bon biomarcador de la competència dels oòcits. L'efecte negatiu de la més alta ràtio de LA:ALA en la competència dels oòcits no estava relacionada, tal com s’havia observat en altres estudis, amb una funció mitocondrial alterada, ni amb un augment de la producció d’espècies reactives d’oxigen o d’estrès del reticle endoplasmàtic com a conseqüència dels resultats obtinguts en l'expressió relativa dels gens estudiats. Per tant, hem hipotetitzat que l'addició d'altes concentracions de LA: ALA es pot relacionar amb una alteració en l'estructura de la membrana plasmàtica causada per una incorporació d'aquests àcids grassos en els fosfolípids de la membrana acompanyats amb el consum d'ATP.Fatty acids (AAGG) are an important source of energy for oocyte growth phase. Therefore, the study of follicular fluid (FF) where they mature, is of special interest. In previous studies, Romaguera et al. (2011) concluded that oocytes from large follicles (≥ 3mm) were more competent than the small follicles. Moreover, Catalá et al. (2015) showed that there was a differential production of embryos between seasons, being significantly lower in autumn than in winter. Our hypothesis was that the FA profile of FF from prepubertal and adult goats, as well as from different follicle sizes and different seasons, could give us information of the oocyte competence. Our objective was to determine whether this profile could be used as a molecular marker for the quality oocytes. In the first experiment, we analysed the profile of FA in FF. Among others, we found differences in total AAGG acids (PUFA), and n6: n3 ratio according to age, size of the follicle and seasons. In the second experiment, we evaluate the competence of oocytes from prepubertal females adding different ratios of linoleic acid (LA: n6 PUFA) and α-linolenic acid (ALA: n3 PUFA) in IVM. We observed ratio LA: ALA 200: 50 µM had a detrimental effect on embryo development of oocytes when compared with control groups and other treatments (100: 50 and 50:50 µM) when oocytes were in vitro fertilized (IVF) (≈ 2.63% vs 13%) but not when they were activated partenogenèticament. According to the results of the experiment 2, the aim of the experiment 3 was to study the effect of LA:ALA ratios on prepubertal goat oocyte quality by assessing mitochondrial distribution and activity, ATP concentration and relative gene expression. Assessing mitochondrial activity, active mitochondria distribution and ATP concentration in the oocyte, we found that there was a change in this parameters when they were analysed on immature oocytes (collection point) compared to IVM oocytes (after 24 h of maturation). Moreover, the addition of 200:50 µM at IVM modified the mitochondrial activity of these oocytes, being higher compared with the other treatment groups, but no changes were observed in the active mitochondria distribution or ATP concentration. Concerning mRNA relative expression, we analysed 9 genes that are shown to be altered if the cell is under stress, and which development could be compromised: ATF4, DNMT1, GAPDH, GCLC, GPX1/GSH-Px, HSPA5/GPR78, RPL19, SLC2A1/GLUT1, SOD1/CuZnSOD. Among these genes, GPX1, RPL19 and SOD1 showed significant differences when comparing immature and IVM oocytes, but not among groups of treatment. In conclusion, we found that FA profile of goat FF is similar to the follicular fluid found in cows, sheep and woman. The main differences that we found in goats were mainly due to the age of the female. However, we found a direct relationship between n6:n3 PUFA composition in follicular fluid regarding follicular size and season of the year, with previous results in our lab suggesting that this ratio could be a biomarker of oocyte competence. Moreover, we found that adding 200:50 µM LA:ALA had a detrimental effect on blastocyst production of prepubertal goat oocytes produced by IVF but not by parthenogenetic activation. Contrarily to what was previously concluded in another studies found in the literature, the negative effect of the highest LA:ALA ratio on oocyte competence was not related to impaired mitochondrial function, ROS production or ER stress according to the relative expression of the studied genes. Thus, we hypothesized that the effect of the addition of high concentrations of LA:ALA was related to an alteration on the structure of the plasma membrane caused for an incorporation of these fatty acids in the membrane phospholipids accompanied with ATP consumption.
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Fernandez, Esther Collado. "Molecular and metabolic measures of oocyte developmental competence in vivo and in vitro." Thesis, University of Leeds, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.713491.
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Assisted reproduction technologies remain inefficient, owing largely to poor oocyte quality. It is hypothesised that a more detailed understanding of the factors that influence the oocyte's metabolome and transcriptome in vivo and in vitro will lead to improvements in the diagnosis and treatment of female infertility. The objectives of this thesis were to (i) evaluate the impact of the follicular environment in natural cycles and following controlled ovarian stimulation (COS) on oocyte competence (i.e. quality) in vitro; (ii) identify cumulus cell markers of oocyte quality; and (iii) map the changes in oocyte carbohydrate metabolism and mitochondria] membrane potential (4Wm) during oogenesis. In vitro maturation (IVM) was conducted in 426 bovine oocytes from natural cycles and 102 oocytes were obtained from follicles after COS. Oocyte quality was quantified by meiotic progression to metaphase 11 (MII), by amino acid profiling (AAP) and by tracking the gamete's capacity to fertilise and develop into blastocyst. Oocytes from subordinate follicles, follicles ipsilateral to the corpus luteum, and follicles 5-9.5mm in diameter showed greater developmental potential. The consumption/production of serine, threonine, histidine and glutamine by bovine MII oocytes was predictive (68.9% accuracy) of the gametes capacity to support blastocyst development in vitro. A high ratio of inhibin 13a (INHBA) to follistatin (FST) mRNA expression in cumulus cells (CCs) also reflected the blastocyst potential of bovine oocytes. Analysis of the consumption/production of glucose, lactate and pyruvate by 292 ovine and 729 human follicles and 211 ovine and 275 human oocytes showed that energy metabolism by these cells relied on glucose and pyruvate oxidation, respectively, and this increased as development progressed. Oocyte mitochondria] i.'Pm remained stable through oogenesis. The results indicate that the follicle microenvironment profoundly influences oocyte metabolism and developmental potential in monovular species. Furthermore, follicular maturity, oocyte AAP and CC gene expression have been shown to be valuable markers of oocyte quality in vitro.
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Gracia, Catalá Maria. "Assessment of prepubertal sheep oocyte competence for in vitro embryo production by the Brilliant Cresyl Blue test." Doctoral thesis, Universitat Autònoma de Barcelona, 2012. http://hdl.handle.net/10803/96655.
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La calidad de los oocitos es sinónimo de competencia oocitaria y se define como la capacidad de un oocito para reanudar la meiosis, dividirse después de la fertilización, desarrollarse hasta la etapa de blastocisto, inducir la preñez y conseguir el nacimiento de un animal sano. La selección de los oocitos más competentes es un punto clave en los programas de producción in vitro de embriones (PIVE).
El test de Azul de Cresol Brillante (BCB) es un método no invasivo que separa los oocitos que han finalizado su crecimiento (BCB+: citoplasma azul) de los oocitos con la enzima G6PDH activa o oocitos en proceso de crecimiento (BCB-: citoplasma incoloro). En esta tesis, hemos llevado a cabo 3 estudios para probar la capacidad del BCB en seleccionar los oocitos más competentes para la producción in vitro de embriones utilizando corderas como donantes de oocitos. Además se estudiará la competencia oocitaria en relación con el citoplasma y factores moleculares, sus respuestas a las diferentes técnicas de fecundación y nuevos medios de maduración para mejorar la PIVE.
En el Experimento 1, se analizaron diferentes concentraciones del BCB (13, 26, 39 y 52 µM) y los oocitos fueron MIV-FIV y CIV. Se evaluó: diámetro de los oocitos, actividad mitocondrial, actividad del factor promotor de la maduración (MPF), la expresión de genes relacionados con el metabolismo (ATP1A1 y COX1) y la función constitutiva de la célula (CPEB y S100A10) y el desarrollo hasta el estadio de blastocisto. Los resultados mostraron que 13 µM de BCB es una concentración adecuada que diferencia los oocitos más grandes (BCB+: 123,66 µm), competentes para desarrollar hasta blastocisto (21%) y con más células (69,71±6,19) que los BCB- (106,82 µm, 9% y 45,91±3,35, respectivamente). La actividad mitocondrial fue mayor en los BCB+ que en los BCB- (3369 y 1565 unidades arbitrarias, respectivamente) y también la actividad de MPF (1,479±0,09 y 1,184±0,05 densidad óptica, respectivamente). La expresión de genes no mostró correlación con la calidad de los oocitos.
El objetivo del experimento 2 fue mejorar la producción in vitro de los oocitos BCB- mediante la adición de insulina transferrina selenio y ácido ascórbico durante 12 y 24 h de la MIV. El MPF y el contenido de ATP se midieron antes y después de la MIV. Los resultados no mostraron diferencias en la producción de blastocistos entre los oocitos BCB-. El MPF y el ATP aumentaron en todos los grupos (P <0,001) después de la MIV.
En el Experimento 3 se estudiaron técnicas de fecundación como la FIV, ICSI y la activación partenogénetica (AP) en los oocitos BCB+ y BCB-. Se analizó el contenido del ATP intracelular. Los oocitos BCB+ tuvieron un desarrollo hasta blastocito significativamente mayor tras la FIV y la AP (31,7% y 20,5%, respectivamente) que los BCB- (6,7% y 8,8%, respectivamente). Sin embargo los oocitos inyectados (ICSI) no mostraron diferencias en los blastocistos producidos entre los BCB+ y BCB- (14,3% vs 11,8%, respectivamente). Los oocitos BCB+ mostraron tener mayor concentración de ATP que los BCB-.
Finalmente podemos concluir que el test del BCB es una metodología fácil, rápida y adecuada para seleccionar los oocitos de corderas más competentes. Los oocitos BCB+ mostraron una mayor producción de blastocistos, actividad mitocondrial y del MPF y mayor contenido de ATP que los BCB-. El test de BCB es un método útil para ser incorporado en los protocolos de PIVE cuando se trabaja con un gran y heterogéneo número de oocitos. Sin embargo este test es menos interesante cuando se trabaja con un pequeño número de oocitos, como en laparoscópica o ICSI.The oocyte quality is used as synonymous of oocyte competence defined as the ability of an oocyte to resume meiosis, cleave following fertilization, develop to the blastocyst stage, induce a pregnancy and bring the offspring to term in good health. The selection of more competent oocytes is an important point in in vitro embryo production programs. The Brilliant Cresyl Blue (BCB) test has been successfully used as a non invasive methodology to classify oocytes according to their cytoplasm coloration as grown (BCB+: blue cytoplasm) or growing (BCB-: colorless cytoplasm) oocytes. To our knowledge there are no previous reports using this test to select competent oocytes in sheep. We have carried out 3 studies to test the ability of the BCB to select the most competent prepubertal sheep oocytes for in vitro blastocyst embryo production. Furthermore, we pretend to improve the knowledge about oocyte competence related to their cytoplasmic and molecular performances, their responses to different techniques of fertilization and to test new maturation media to improve the blastocyst production. In Experiment 1, different concentrations of the BCB test (13, 26, 39 and 52 µM) were analyzed. After BCB culture all of oocytes were IVM-IVF and IVC. The parameters assessed in this study were: oocyte diameter, mitochondrial activity, maturation-promoting factor (MPF) activity, mRNA relative expression (RE) of genes related to metabolism (ATP1A1 and COX1) and constitutive function of the cell (CPEB and S100A10) and the blastocyst development. The results showed that 13 µM BCB during 60 min could be a suitable concentration to differentiate largest (BCB+, 123.66 µm) and most competent oocytes to develop to the blastocyst stage (21%) and with a higher number of cells (69.71±6.19 S.E.M.) compared with non-stained BCB- oocytes (106.82 µm, 9% and 45.91±3.35 S.E.M., respectively). Mitochondrial activity, assessed by MitoTracker Orange CMTMRos probe, was significantly higher in BCB+ than in BCB- oocytes after in vitro maturation (3369 and 1565 Arbitrary Units, respectively) and the MPF activity, assessed by CDC2 kinase activity assay, showed significantly higher activity at metaphase II stage in BCB+ than in BCB- oocytes (1.479±0.09 and 1.184±0.05 optical density, respectively). The mRNA RE of the different genes analyzed in this work did not show a correlation with the oocyte quality. In Experiment 2, the objective was to improve blastocyst production of small (BCB-) oocytes by addition of Insulin Transferrin Selenium and Ascorbic Acid during 12 and 24 h of IVM. MPF and ATP content were measure before and after IVM. Results showed no differences in blastocyst production between BCB oocytes. The MPF and ATP increased in all groups (P<0.001) after the IVM. In Experiment 3, the aim was to test the blastocyst production after IVF, ICSI and PA of BCB+ and BCB- oocytes. ATP content was analyzed. BCB+ oocytes developed significantly higher up to the blastocyst stage after IVF and PA (31.7% and 20.5%, respectively) than BCB- (6.7% and 8.8%, respectively) oocytes. However, ICSI treated oocytes did not show these differences between BCB+ and BCB- oocytes (14.3% vs 11.8%, respectively). BCB+ oocytes had significantly more ATP content than BCB- oocytes. Finally we can conclude that the BCB test is an easy, fast and suitable methodology to select the more competent sheep oocytes. Good quality oocytes (BCB+) showed higher blastocyst production, mitochondrial and MPF activity and ATP content than BCB- oocytes. The BCB test is a useful method to be incorporated in the embryo production protocol where a large and heterogeneous number of oocytes are use to be in vitro fertilized. However, BCB test is less interesting when working with a small number of oocytes such as in Laparoscopic Ovum Pick Up (LOPU) or ICSI.
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Soto, Heras Sandra. "Oocyte competence: Study of melatonin and meiotic inhibitors to improve in vitro embryo production in juvenile goats." Doctoral thesis, Universitat Autònoma de Barcelona, 2019. http://hdl.handle.net/10803/667266.
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La producción in vitro de embriones (PIVE) tiene su mayor limitación en la eficacia de la maduración in vitro (MIV) de los oocitos. La MIV altera la competencia de los oocitos debido al efecto perjudicial de los radicales de oxígeno (ROS) y a la reanudación rápida y espontanea de la meiosis. En oocitos de cabras de 1 a 2 meses de edad, estos dos factores son más intensos y perjudiciales. En esta tesis, se plantearon dos estrategias para mejorar los protocolos de MIV en estos oocitos: A) Suplementar el medio de MIV con melatonina como potente antioxidante para disminuir los ROS; B) Diseñar un sistema bifásico de MIV con una fase de pre-maduración (pre-MIV) con inhibidores de la meiosis, seguida por una segunda fase de MIV convencional.
El efecto de la melatonina fue evaluado en dos estudios. En el primero, se testaron diferentes concentraciones de melatonina (10-11, 10-9, 10-7, 10-3 M) en el medio de MIV. La suplementación con 10-7 M de melatonina aumentó el porcentaje de blastocistos (28.9% vs. 11.7% en el control) y redujo el nivel intra-oocitario de ROS. En el segundo estudio, evaluamos los mecanismos de acción de la melatonina (10-7 M) en los oocitos y detectamos la presencia del receptor de melatonina 1 (MT1) en oocitos y células del cúmulo mediante inmunocitoquímica. La melatonina incrementó la actividad mitocondrial y el ATP de los oocitos, redujo los ROS y mejoró la calidad de los blastocistos producidos in vitro (55.8 vs. 30.4 células de la masa celular interna), comparado con el grupo control sin antioxidantes. No pudimos determinar si estos efectos son mediados por el MT1 porqué el grupo melatonina más lucindol (antagónico del MT1) no mostró diferencias significativas respeto los grupos melatonina y control.
La estrategia para mejorar la competencia de los oocitos mediante una pre-MIV con inhibidores meióticos se desarrolló en dos estudios. El primer estudio se llevó a cabo en la Universidad de Adelaida (Australia) en oocitos de bovino adulto. Evaluamos el efecto de distintas concentraciones del péptido natriurético tipo C (CNP; 50, 100, 200 nM) y el 3-isobutyl-1-methylxanthine (IBMX; 500 µM) sobre el arresto meiótico durante 6 y 24 h. El cultivo de pre-MIV con CNP (100 nM) más IBMX durante 6 horas obtuvo el mayor efecto de parada meiótica (92% de oocitos en vesícula germinal; VG). A continuación, diseñamos un sistema bifásico utilizando este protocolo de pre-MIV, seguido de 20 h de MIV convencional, y comparamos con una MIV control (24 h). La MIV bifásica prolongó la comunicación entre células del cúmulo y oocito, evaluada mediante la densidad de proyecciones de transzona (TZP), mejoró la actividad mitocondrial y aumentó la producción de blastocistos (45.1% vs. 34.5%). En el segundo estudio, analizamos un sistema similar en oocitos de cabras de 1 a 2 meses de edad. Primero, evaluamos el efecto de distintas dosis de CNP (50, 100, 200 nM) con o sin la adición de 10 nM de estradiol. La pre-MIV con CNP (200 nM) más estradiol mantuvo un 74.7% de oocitos en VG y una alta densidad de TZP durante 6 h. En segundo lugar, cultivamos los oocitos con MIV bifásica (6 h pre-MIV más 24 h MIV) comparado con MIV control (24 h). La MIV bifásica incrementó el glutatión intra-oocitario y disminuyó los ROS, aumentó la expresión de DNA metiltranferasa 1 y proteína 6 estimuladora de TNF en complejos cúmulo-oocito (COCs), y mejoró la producción de blastocistos (30.2% vs. 17.2%).
En conclusión, la MIV con melatonina y la pre-MIV con inhibidores meióticos son métodos que pueden mejorar sustancialmente la competencia de los oocitos de hembras muy jóvenes para producir embriones in vitro.Oocyte in vitro maturation (IVM) is a limiting step for the in vitro embryo production (IVEP). Conventional IVM can impair oocyte competence due to the damaging effect of reactive oxygen species (ROS) and the rapid and spontaneous meiotic resumption. These two factors are more intense and damaging for oocytes of juvenile goats (1-2 months old). In the present thesis, we hypothesized that two different strategies could improve IVM protocols in these oocytes: A) Supplementing the IVM medium with melatonin as a powerful antioxidant in order to reduce ROS; B) Designing a biphasic IVM system including a pre-maturation (pre-IVM) culture phase with meiotic inhibitors, followed by a conventional IVM phase. The effect of melatonin was evaluated in two studies. In the first study, various melatonin concentrations (10-11, 10-9, 10-7, 10-3 M) were tested in the IVM medium. The supplementation with 10-7 M of melatonin increased the blastocyst rate (28.9% vs. 11.7% in control) and decreased intra-oocyte ROS levels after IVM. In the second study, the mechanisms of action of melatonin (10-7 M) in the oocyte were assessed and the presence of melatonin receptor 1 (MT1) was detected in oocytes and cumulus cells by immunocytochemistry. Melatonin increased oocyte mitochondrial activity and ATP content, decreased intra-oocyte ROS levels, and improved blastocyst quality (55.8 vs. 30.4 cells in the inner cell mass), compared to control group without antioxidants. However, we could not determine if these effects were mediated by MT1 because IVM with melatonin plus luzindole (an inhibitor of MT1) showed no significant differences compared to melatonin and control groups. The strategy for improving oocyte competence during a pre-IVM culture with meiotic inhibitors was also developed in two studies. The first study was performed at the University of Adelaide (Australia) with oocytes from adult cow. We evaluated the effect of various concentrations of C-type natriuretic peptide (CNP; 50, 100, 200 nM) and 3-isobutyl-1-methylxanthine (IBMX; 500 µM) on oocyte meiotic arrest during 6 and 24 h. Pre-IVM culture with CNP (100 nM) plus IBMX for 6 h showed the greater effect on the meiotic arrest (92% of oocytes in germinal vesicle; GV). We developed a biphasic IVM system using this pre-IVM protocol followed by 20 h of conventional IVM, and compared to control IVM (24 h). Biphasic IVM prolonged cumulus-oocyte communication assessed by the density of transzonal projections (TZP), improved oocyte mitochondrial activity and increased blastocyst rate (45.1% vs. 34.5%). In the second study, a similar biphasic IVM system was tested in juvenile-goat IVEP. First, the effect of various CNP doses (50, 100, 200 nM) were tested with and without the addition of 10 nM estradiol. Pre-IVM with CNP (200 nM) plus estradiol sustained 74.7% of oocytes in GV and a high density of TZPs during 6 h. Second, oocytes were cultured with biphasic IVM (6 h pre-IVM plus 24 h IVM) compared to control IVM (24 h). Biphasic IVM increased intra-oocyte glutathione levels and decreased ROS, up-regulated the expression of DNA methyltransferase 1 and TNF-stimulated gene 6 protein in cumulus-oocyte complexes (COCs), and improved blastocyst rate (30.2% vs. 17.2%). In conclusion, IVM with melatonin and pre-IVM with meiotic inhibitors are promising methods that can considerably improve the oocyte developmental competence of very young females for producing embryos in vitro.
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Bernal, Ulloa Sandra Milena [Verfasser]. "Experimental studies into the role of cAMP in bovine oocyte maturation and embryo developmental competence / Sandra Milena Bernal Ulloa." Hannover : Bibliothek der Tierärztlichen Hochschule Hannover, 2016. http://d-nb.info/1104288443/34.
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Abreu, Fernanda Martins de. "The Effect of Progesterone Concentrations during Follicular Development in Cattle on Luteinizing Hormone Secretion, Follicular Development, Oocyte Competence and Fertility." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1420620191.
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Tessaro, I. "LA BOVINA DA LATTE COME MODELLO PER LO STUDIO DEL PRECOCE INVECCHIAMENTO OVARICO: ASPETTI MORFOLOGICI E MOLECOLARI." Doctoral thesis, Università degli Studi di Milano, 2010. http://hdl.handle.net/2434/150039.
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Several studies in women indicate that precocious ovarian aging is a disorder characterized by an accelerated decline of reproductive potential. We demonstrated that ovaries recovered from 4-8 years old dairy cows with a low antral follicle count generate oocytes with low developmental competence, high aneuploidy rate after maturation, a reduced amount of active mitochondria and a lower glutathione synthesis capability. Interestingly, these ovaries have a reduced volume, show a low proportion of healthy primordial follicles and an increased stromal tissue. Moreover this is accompanied by reduced perifollicular vessels and endothelial nitric oxide (NO) synthase concentration. Interestingly, the administration of NO donor molecules partially reverse the defective oocyte developmental capability in vitro.
Finally, follicular fluids recovered from these ovaries have a high progesterone concentration, low estrogen/progesterone ratio and low Anti-Mullerian hormone concentration, which accounts for a low follicle reserve.
Altogether, morphological changes, ovarian and endocrine functions consistently indicate a condition of precocious ovarian failure in young adult dairy cows and validate the use of this population as an animal model to study the accelerated decline of fertility in women.
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Dhawan, Anil. "The role of oocyte- and embryo-secreted factors in cumulus cell differentiation and their relationship to embryo quality and developmental competence." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0028/MQ52295.pdf.
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Li, Chunyang. "Extracting and Visualizing Data from Mobile and Static Eye Trackers in R and Matlab." DigitalCommons@USU, 2017. https://digitalcommons.usu.edu/etd/6880.
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Eye tracking is the process of measuring where people are looking at with an eye tracker device. Eye tracking has been used in many scientific fields, such as education, usability research, sports, psychology, and marketing. Eye tracking data are often obtained from a static eye tracker or are manually extracted from a mobile eye tracker. Visualization usually plays an important role in the analysis of eye tracking data. So far, there existed no software package that contains a whole collection of eye tracking data processing and visualization tools. In this dissertation, we review the eye tracking technology, the eye tracking techniques, the existing software related to eye tracking, and the research on eye tracking for posters and related media. We then discuss the three main goals we have achieved in this dissertation: (i) development of a Matlab toolbox for automatically extracting mobile eye tracking data; (ii) development of the linked microposter plots family as new means for the visualization of eye tracking data; (iii) development of an R package for automatically extracting and visualizing data from mobile and static eye trackers.
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Velazquez, Cabrera Miguel Abraham [Verfasser]. "The influence of insulin-like growth factor 1 on in vivo oocyte developmental competence and in vitro preimplantation embryo development in cattle / Miguel Abraham Velazquez Cabrera." Hannover : Bibliothek der Tierärztlichen Hochschule Hannover, 2010. http://d-nb.info/1004264135/34.
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Santos, Elisa Caroline da Silva. "Seleção de oócitos suínos através de Brilliant Cresyl Blue." Universidade Federal de Pelotas, 2014. http://guaiaca.ufpel.edu.br/handle/123456789/1232.
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Previous issue date: 2014-02-18The production of swine embryos in vitro requires efficient in vitro maturation (IVM), which can be achieved by selection the most competent cumulus-oocyte complexes COC).The Brilliant Cresyl Blue (BCB) dye allows the selection of COC with complete growth by assessing their levels of the G6PDH enzyme. However, there is a possible negative effect of selection with BCB. This effect may be due to its intrinsic toxicity or to factors related to the composition of the media used during the test. This research had the objectives: to determine potential toxicity after exposure to BCB and to evaluate the effect of different medias for BCB staining on the ability to support oocyte development. On the first research, after BCB staining and after IVM, several tests were performed to evaluate the effects of their potential toxicity on mitochondrial activity and functionality: reactive oxygen species (ROS), ATP, mitochondrial membrane potential and the number of copies of mitochondrial DNA. The results showed that oocytes stained with BCB produced high levels of ROS, compared with control immediately after staining and after the IVM. The ATP and mitochondrial membrane potential showed similar results between groups after staining, however, after IVM oocytes BCB showed lower membrane potential and ATP. There was no difference in the number of copies of mtDNA in the evaluated groups. Already, on test of ATP content in early embryos, ATP was lower in BCB oocytes, however, there was no difference statistical. In second study, the most commonly used media, D-PBS, was compared with a more elaborate media for BCB called here: ReproPEL. The COC s submitted to both media were submitted to nuclear and cytoplasmatic maturation, parthenogenetic activation, and to the comet test. The great rates of nuclear IVM (P<0.05) were obtained for DPBS+ (63.1%), ReproPELc (55.1%) and ReproPEL+ (50.2%). The group with smaller area of CG (P<0.05), showing better migration, were ReproPELc, D-PBS+, D-PBS- and ReproPEL+. The parthenogenetic activation indicated that ReproPEL media presented satisfactory capacity of oocyte maintenance, resulting in acceptable rates of development to blastocyst stage: 13.0% for ReproPEL+; and 12.7% for ReproPELc. So, the ReproPEL media can be used for maintenance of swine oocytes, but it was not the most appropriate media for BCB staining. Moreover, after exposure to BCB and after IVM, BCB oocytes presented high toxicity at mitochondrial level, due to increased production of ROS, decreased membrane potential and compromised ATP production. However, the mitochondrial function was restored in early embryonic development. In conclusion, BCB was responsible for toxicity in immature swine oocytes, nevertheless, further studies must be performed to evaluate the changes caused by BCB in the embryonic level.
Para a obtenção de embriões suínos produzidos in vitro faz-se necessário que a maturação in vitro (MIV) ocorra de forma eficiente, o que exige a seleção dos complexos cumulus-oócitos (CCOs) mais competentes. O corante Brilliant Cresyl Blue (BCB) permite selecionar os CCOs que completaram seu crescimento, mediante a avaliação dos níveis da enzima G6PDH. Entretanto, existe um possível efeito nocivo relacionado ao processo de seleção com BCB, o qual pode ser devido a uma toxicidade intrínseca do corante ou aos vários fatores relacionados à composição dos meios para a realização do teste. Desta forma, esta pesquisa teve como objetivos: averiguar a existência de toxicidade após exposição ao BCB e avaliar o efeito de diferentes meios para a coloração com BCB sobre a capacidade de suporte ao desenvolvimento oocitário. Na primeira pesquisa, após a coloração com BCB e após a MIV, vários testes foram realizados para avaliar os efeitos de sua potencial toxicidade sobre a atividade e a funcionalidade mitocondrial: análises de espécies reativas de oxigênio (ROS), ATP, potencial de membrana mitocondrial e número de cópias de DNA mitocondrial. Como resultados, obteve-se que oócitos corados com BCB produziram altos níveis de ROS quando comparados com o controle imediatamente após a coloração e após a MIV. O ATP e potencial de membrana mitocondrial apresentaram resultado similar entre os grupos após a coloração, porém, após a MIV oócitos BCB apresentaram menor potencial de membrana e ATP. Não ocorreu diferença no número de cópias do DNAmt nos grupos avaliados. Já, no teste do conteúdo de ATP em embriões iniciais, o ATP foi inferior em oócitos BCB, porém, não ocorreu diferença significativa. Na segunda pesquisa, comparou-se o meio mais utilizado, D-PBS, com um meio mais elaborado para o BCB, chamado de ReproPEL. Os CCOs submetidos aos dois meios foram submetidos à MIV e avaliados quanto à maturação nuclear e citoplasmática, ativação partenogenética e ao teste cometa. Na MIV nuclear, as maiores taxas de MII (P<0,05) foram obtidas no DPBS+ (63,1%), ReproPELc (55,1%) e ReproPEL+ (50,2%). Quanto à densidade dos GC, os grupos com menor área (P<0,05), evidenciando melhor migração, foram ReproPELc, D-PBS+, D-PBS- e ReproPEL+. A ativação partenogenética demonstrou que o meio ReproPEL possui boa capacidade de manutenção oocitária, possibilitando taxas aceitáveis de desenvolvimento até o estágio de blastocisto: ReproPEL+ (13,0%); e ReproPELc (12,7%). Desta forma, o meio ReproPEL pode ser indicado para a manutenção oocitária, porém não foi o meio mais indicado para o corante BCB. Com relação à toxicidade, após a exposição ao BCB e após a MIV, os oócitos BCB apresentaram alterações em nível mitocondrial, devido ao aumento na produção de ROS, diminuição do potencial de membrana e ao comprometimento da produção de ATP. Porém, a função mitocondrial foi restaurada no início do desenvolvimento embrionário. Com tudo isso, conclui-se que o BCB foi responsável por toxicidade em oócitos suínos imaturos, sendo necessários novos estudos para avaliar as alterações causadas pelo BCB em nível embrionário.
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Puard, Vincent. "Marqueurs non-invasifs de la compétence ovocytaire au développement dans les cellules de cumulus chez l'humain." Thesis, Tours, 2013. http://www.theses.fr/2013TOUR3310/document.
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Prédire la capacité de développement et d'implantation des embryons reste un enjeu majeur pour l’Assistance Médicale à la Procréation (AMP). L’AMP doit répondre au désir du couple d’avoir un enfant en limitant les risques encourus par la mère et l’enfant en cas de grossesse multiple. Tous les laboratoires d’AMP utilisent des critères morphologiques pour évaluer la compétence au développement des embryons en dépit de la faible valeur prédictive de cette analyse. L'interaction ovocyte-cumulus participe à l’acquisition par l'ovocyte de sa compétence au développement. Cette interaction met en jeu l’expression de gènes spécifiques dans les cellules de cumulus (CCs). Notre objectif était d'identifier des marqueurs non invasifs de la compétence ovocytaire au développement. Ainsi nous avons recherché au niveau des CCs des gènes et des protéines exprimés en fonction de l’aptitude de l’ovocyte fécondé à atteindre le stade de blastocyste. L'expression des gènes des CCs a été étudiée par puce à ADN et qPCR haut débit. Après avoir tenu compte de la variabilité des patientes, nous avons identifié les gènes RGS2, POLR3K et CUL4B comme biomarqueurs. L'expression des protéines des CCs a été étudiée par puce à protéines et après validation des anticorps ciblant les protéines d'intérêt, les protéines RGS2, POLR3K et MERTK ont été identifiées comme biomarqueurs de la compétence au développement de l'ovocyte. Ces résultats permettent d’envisager la création d’un modèle prédictif multicritère incluant la morphologie de l’embryon à J2, les gènes et protéines marqueursThe ability to predict the developmental and implantation ability of embryos remains a major goal in human assisted reproductive technology (ART).ART should allow couple to become parents while limiting the risks to the mother and the child in case of multiple pregnancy. ART laboratories use morphological criteria to evaluate the oocyte competence despite the poor predictive value of this analysis. The oocyte-cumulus interaction helps the oocyte to acquire its developmental competence partly through the expression of specific genes at the cumulus level. Therefore our aim was to identify at the level of cumulus cells (CCs) genes and proteins related to oocyte developmental competence as non-invasive marker. Gene expression of CCs was studied using microarray and high throughput qPCR according to the developmental competence of the oocyte (ability to reach the blastocyst stage after fertilization). While taking into account the patient variability we identified RGS2, POLR3K and CUL4B as biomarkers at RNA level. Then protein expression of CCs was studied using Reverse Phase Protein Array. After validation of the antibodies targeting the proteins of interests, RGS2, POLR3K and MERTK were identified as protein biomarkers of the developmental competence of the oocyte. These results lead us to consider a multi variables predictive model including the morphology of the embryo at J2, genes and protein markers
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Bagg, Melanie Anna. "Factors affecting the developmental competence of pig oocytes matured in vitro." 2007. http://hdl.handle.net/2440/42908.
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Pre-pubertal pig oocytes possess lower developmental competence than those from adult pigs following in vitro maturation (IVM). Previous studies have demonstrated that exposure of pre-pubertal oocytes to 1 mM dibutyryl cAMP (dbcAMP), a membrane permeable cyclic adenosine monophosphate (cAMP) analogue, for the first 20 h of IVM improves the rate of blastocyst development. Developmental competence of in vitro matured pig oocytes has been reported to increase with increasing follicle size. In this thesis, experiments were carried out using pre-pubertal and adult pig oocytes to investigate the relationship between donor age, intra-oocyte cAMP level and follicle size in terms of oocyte maturation and developmental competence. These experiments demonstrated that, while ovarian, follicular and oocyte morphology are immediately altered with the onset of puberty, pre-pubertal oocytes must be exposed to more than the first oestrous cycle to achieve improved developmental competence in vitro. Later experiments demonstrated that pre-pubertal oocytes accumulate less cAMP during IVM, undergo more rapid meiotic progression and display reduced rates of blastocyst development compared to in vitro matured adult oocytes. Treatment with dbcAMP for 22 h IVM increased the cAMP content of pre-pubertal oocytes, slowed meiotic progression during IVM and improved the rate of blastocyst formation. While the cAMP concentration of pre-pubertal oocytes was increased to levels similar to that of adult oocytes, rates of blastocyst formation remained lower, suggesting that additional factor(s) are required for oocyte maturation. This thesis also examined the follicle size cohorts that make up the 3-8 mm aspiration range on pig ovaries. The surface of pre-pubertal ovaries contained around double the number of 3 mm follicles compared with adult ovaries. Blastocyst development of pre-pubertal oocytes increased with increasing follicle size and was highest using oocytes from 5-8 mm follicles, while adult oocytes from all follicle size cohorts displayed similar high rates of blastocyst formation. The interaction between follicle size and cAMP content in pre-pubertal oocytes was examined next. Cumulus-oocyte complexes (COCs) from 3 mm follicles accumulated less intra-oocyte and inter-COC cAMP and displayed reduced cumulus expansion compared with COCs from 5-8 mm follicles. While dbcAMP treatment increased the cAMP content of oocytes from 3 mm follicles, it had no effect on the cAMP content of the whole COC. These findings suggest that inadequate levels of intra-oocyte cAMP during IVM contribute to the low developmental competence of pre-pubertal oocytes from 3 mm follicles, suggesting that cAMP transfer, production or degradation processes are incomplete. Analysis of steroid content from different follicle size cohorts revealed that the progesterone content of prepubertal follicular fluid (FF) increased with increasing follicle size, yet overall was lower than that of adults. This suggests that differences may exist in the gonadotropinstimulated steroidogenic activity of granulosa cells of pre-pubertal COCs from different follicle sizes. Since progesterone secretion did not differ between pre-pubertal and adult COCs, it appears that the downstream pathway from the granulosa cell response rather than the actual quantity of progesterone is important for subsequent maturation processes. These studies then examined gap junction communication (GJC) within the pre-pubertal COC during IVM to examine whether the positive effects of increasing follicle size and dbcAMP on intra-oocyte cAMP levels relates to improved cAMP transfer between the cumulus cell layer and oocyte. Cumulus cell-oocyte GJC during IVM was maintained for a longer period in pre-pubertal COCs from 3 mm follicles than in those from 5-8 mm follicles. Treatment with dbcAMP had minimal effect on GJC in either COC type, thus the dbcAMP-induced increase in intra-oocyte cAMP levels appears independent of GJC. Differences in GJC during IVM together with the COCs ability to increase intraoocyte cAMP levels during IVM, suggests that differences may exist in the quantity of gonadotropin receptors, which are responsible for cAMP production, within the cumulus layer of COCs from 3 mm compared with 5-8 mm follicles. In conclusion, this thesis has demonstrated that an increase in intra-oocyte cAMP is necessary during maturation for completion and synchronisation of maturation and high developmental competence of the pig oocyte. Comparison of 3, 4 and 5-8 mm follicle sizes in the pre-pubertal pig, as described here, provides an excellent model for further investigation into the role of cAMP and the other factors required for co-ordination of oocyte nuclear and cytoplasmic maturation and subsequent embryo production.http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1297309
Thesis (Ph.D.) -- School of Paediatrics and Reproductive Health, 2007
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Tseng, Jung-Kai, and 曾榮凱. "Alterations in developmental competence and cellular parameters of heat-shocked porcine oocytes." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/56836702157742606357.
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博士中興大學
動物科學系所
95
The objectives of this study were to determine the effect of a short-term heat shock (HS) on the developmental competence and cellular physiology including expression of heat shock protein 70 (hsp 70), apoptosis and alteration of intracellular calcium concentration ([Ca2+]i) of the in vitro matured (IVM) porcine oocytes. Cumulus-oocyte-complexes (COCs) were collected from local abattoirs and were IVM in NCSU-23 medium for 42 h. Matured oocytes were selected and randomly allocated to different treatment groups. The COCs were cultured at 39 ℃ for 0 or 4 h in the control groups (without HS) and at 41.5 ℃ for 1, 2, or 4 h in the HS groups. The expression of hsp70 was not significantly different among all groups. TUNEL-positive signals (apoptosis) was not observed in the heated oocytes compared to the Controls, but the intensity of Annexin V-FITC signals increased with the duration of HS and in vitro culture. The cleavage and blastocyst rates were declined after more than 2h HS. In addition, The Ca2+ releasing ability of matured oocytes was enhanced by a shorter duration (2h) of HS, but it declined after prolonged heat exposure and in vitro culture. After spindles/chromosomes were exchanged between non-HS oocytes and HS2h oocyets, different sensitivity of the nucleus and the ooplasma was not clearly observed. The physiologic effects and mechanisms of HS on oocytes are complex processes. HS causes multiple changes of the oocyte including enzymatic reactions, ionic influxes, DNA structure and cytoskeleton, etc. Changes in the [Ca2+] of oocytes in response to signaling molecules after different intensities of HS may be important to evaluate their developmental competence. The delicate equilibrium between the deleterious effects and thermotolerance of oocytes or embryos in response to HS is a decisive factor determining their developmental destiny. This study provides clues for further investigations to clarify the mechanism of thermal resistance in oocytes. Further investigations will be focused on regulation of Ca2+-related kinases and looking into their encoding genes responsible for regulation of thermotolerance.
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Arlotto, Theresa Michele. "Acquisition of meiotic competence in bovine oocytes and resolution of a model system for study." 1994. http://catalog.hathitrust.org/api/volumes/oclc/32104544.html.
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Thesis (Ph. D.)--University of Wisconsin--Madison, 1994.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 160-182).
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Kuchenbrod, Lauren Marie. "Effect of serum and hormone supplementation on the competence of oocytes selected by brilliant cresyl blue staining." 2008. http://www.lib.ncsu.edu/theses/available/etd-05122008-205915/unrestricted/etd.pdf.
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Mohammadi-Sangcheshmeh, Abdollah [Verfasser]. "Developmental competence of equine oocytes after ICSI : implications on technical, morphological and cellular aspects / von Abdollah Mohammadi-Sangcheshmeh." 2010. http://d-nb.info/1003262112/34.
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Kito, Seiji. "Epigenetic regulation of hamster oocyte maturation in vitro requirements for production of competent oocytes /." 1996. http://catalog.hathitrust.org/api/volumes/oclc/36221885.html.
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Thesis (Ph. D.)--University of Wisconsin--Madison, 1996.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 176-197).
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Hussein, Tamer. "Role of oocyte-secreted factors in prevention of cumulus cell apoptosis and enhancement of oocyte developmental competence." 2006. http://hdl.handle.net/2440/58191.
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Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library.Paracrine factors secreted by the oocyte (oocyte-secreted factors, OSFs) regulate a broad range of cumulus cell functions. The capacity of oocytes to regulate their own microenvironment by OSFs may in turn contribute to oocyte developmental competence. The aim of this thesis was to examine whether cumulus cells exhibit a low incidence of apoptosis due to their close association with oocytes and their exposure to OSFs, and to investigate if OSFs have a direct influence on bovine oocyte developmental competence during in vitro maturation (IVM). This thesis includes a series of studies designed to examine by various means the nature of the paracrine network of bone morphogenetic proteins (BMPs) and their binding proteins involved in the regulation of cumulus cell apoptosis. OSFs, in particular BMP- 15 and BMP-6, but not growth differentiation factor 9 (GDF-9), reduced apoptosis of cumulus cells by following a gradient from the site of the oocytes. Morever, follistatin and a BMP6 neutralizing antibody, which antagonized the anti-apoptotic effects of BMP15 and BMP6, respectively, whether alone or combined, blocked ~50% of the antiapoptotic actions of oocytes. These results demonstrated that OSFs, particularly BMP-15 and BMP-6, maintain the low incidence of apoptosis by establishing a localized gradient of bone morphogenetic proteins. Results from the present thesis also demonstrated that OSFs enhance oocyte developmental competence during IVM, whether in their native form as an uncharacterized mix of growth factors secreted by the oocyte, throughout the oocyte maturation period, or as exogenous BMP-15 and GDF-9, during the first 9 hour of IVM. Also, OSFs improved embryo quality as evident by increased blastocyst total and trophectoderm cell numbers. These results were further verified in neutralization experiments of the exogenous growth factors and of the native OSFs. Follistatin and the kinase inhibitor SB-431542, which antagonize BMP-15 and GDF-9, respectively, neutralized the stimulatory effects of the exogenous growth factors, and impaired the developmental competence of control cumulus-oocyte complexes (COCs). The work presented in this thesis has provided multiple lines of evidence that OSFregulation of the COC microenvironment is an important determinant of cumulus cell apoptosis and oocyte developmental programming.
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Thesis (Ph.D.) -- University of Adelaide, School of Paediatrics and Reproductive Health, 2006
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Hussein, Tamer. "Role of oocyte-secreted factors in prevention of cumulus cell apoptosis and enhancement of oocyte developmental competence." Thesis, 2006. http://hdl.handle.net/2440/58191.
Full textAbstract:
Paracrine factors secreted by the oocyte (oocyte-secreted factors, OSFs) regulate a broad range of cumulus cell functions. The capacity of oocytes to regulate their own microenvironment by OSFs may in turn contribute to oocyte developmental competence. The aim of this thesis was to examine whether cumulus cells exhibit a low incidence of apoptosis due to their close association with oocytes and their exposure to OSFs, and to
investigate if OSFs have a direct influence on bovine oocyte developmental competence during in vitro maturation (IVM). This thesis includes a series of studies designed to examine by various means the nature of the paracrine network of bone morphogenetic proteins (BMPs) and their binding proteins involved in the regulation of cumulus cell apoptosis. OSFs, in particular BMP- 15 and BMP-6, but not growth differentiation factor 9 (GDF-9), reduced apoptosis of cumulus cells by following a gradient from the site of the oocytes. Morever, follistatin and a BMP6 neutralizing antibody, which antagonized the anti-apoptotic effects of BMP15 and BMP6, respectively, whether alone or combined, blocked ~50% of the antiapoptotic actions of oocytes. These results demonstrated that OSFs, particularly BMP-15 and BMP-6, maintain the low incidence of apoptosis by establishing a localized gradient of bone morphogenetic proteins. Results from the present thesis also demonstrated that OSFs enhance oocyte developmental competence during IVM, whether in their native form as an uncharacterized mix of growth factors secreted by the oocyte, throughout the oocyte maturation period, or as exogenous BMP-15 and GDF-9, during the first 9 hour of IVM. Also, OSFs improved embryo quality as evident by increased blastocyst total and trophectoderm cell numbers. These results were further verified in neutralization experiments of the exogenous growth factors and of the native OSFs. Follistatin and the kinase inhibitor SB-431542, which antagonize BMP-15 and GDF-9, respectively,
neutralized the stimulatory effects of the exogenous growth factors, and impaired the developmental competence of control cumulus-oocyte complexes (COCs). The work presented in this thesis has provided multiple lines of evidence that OSFregulation of the COC microenvironment is an important determinant of cumulus cell apoptosis and oocyte developmental programming.Thesis (Ph.D.) -- University of Adelaide, School of Paediatrics and Reproductive Health, 2006
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Willingham-Rocky, Lauri A. "Evaluation of oocyte competency in bovine and canine species via non-invasive assessment of oocyte quality." Thesis, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2394.
Full textAbstract:
Traditional methods of oocyte selection for in vitro studies have proven inefficient with respect to achieving a level of predictability for competency. In this study, a novel method of oocyte selection was implemented that identified a relationship between oocyte morphological parameters (as defined by a ratio of a shape factor (SF) to average fluorescence intensity (AFI) and AFI, followed by in vitro fertilization (IVF) and in vitro culture (IVC) using the Well of Well (WOW) method to evaluate oocyte competency. Specifically, we used non-cytotoxic fluorescent molecular probes and multiphoton microscopy to non-invasively characterize spatial localization and functional activity of mitochondria, mitochondrial membrane potential (Δψm), and intracellular calcium activity ([Ca2+]i) using rhodamine 123, JC-1 and Fluo-4, AM, respectively in bovine and canine in vitro matured (IVM) oocytes. Comparison of morphological grading with fluorescence intensity yielded similar trends between all grades of oocytes for both species with no visually obvious, distinct characteristic staining that would permit classification of each oocyte as a specific morphological grade. Our studies confirmed that oocyte mitochondria were homogeneously distributed but primarily localized to the peri- and sub-cortical regions of the oocyte at MII stage for both species. Further, heterogeneously polarized mitochondria were localized to the peri- and sub- cortical regions of the oocyte for both species. In bovine oocytes labeled with Fluo-4, AM, levels of [Ca2+]i were either unremarkable, or very low and limited to the peri-cortical areas, just beneath the oolema. For canine MII stage oocytes, levels of [Ca2+]i were within the same range of AFI as bovine. Ranges of fluorescence intensity compatible for optimal embryo development for bovine and optimal fertilization for canine oocytes were 30-300 and 20-35, and 20-30 and 20-25.5 for rhodamine 123 and Fluo-4, AM, respectively. The optimal range for bovine oocytes imaged with JC-1 was 1.25-2.25 and <6 for canine.
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Acton, Beth Marie. "Mitochondrial contributions to embryogenesis, oocyte developmental competence and physiological consequences of heteroplasmy." 2007. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=478979&T=F.
Full text
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Landsmann, Lukáš. "Úloha SIRT1 během zrání oocytů v podmínkách in vitro." Master's thesis, 2018. http://www.nusl.cz/ntk/nusl-388515.
Full textAbstract:
SIRT1 histone deacetylase acts towards many epigenetic and non-epigenetic targets. The involvement of SIRT1 in oocyte maturation is assumed and the importance of ooplasmic SIRT1 pool for further destiny of matured oocyte is strongly suggested. We hypothesized that SIRT1 play role of the signal molecule in mature oocyte through selected epigenetic and non- epigenetic regulation. We observed SIRT1 re-localization in mature oocyte and the association with spindle microtubules. In matured oocyte, SIRT1 shows a spindle-like pattern and spindle- specific SIRT1 action is supported decreasing α-tubulin acetylation. Based on the observation of histone code in immature and matured oocytes, we suggest that SIRT1 is mostly predestined for epigenetic mode of action in germinal vesicle (GV) of immature oocyte. Accordingly, SIRT1- driven trimethylation of histone H3 on lysine K9 in matured oocyte is considered to be an inheritance of GV epigenetic transformation. Taken together, our observations point out the dual spatiotemporal SIRT1 action in oocyte capable to be switched from epigenetic to the non- epigenetic mode of action readily depending on meiosis progress. Keywords: oocyte, SIRT1, histone, developmental competence, tubuline, epigenetics
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Minge, Cadence Ellen. "Diet-induced obesity influences oocyte developmental competence via peroxisome proliferator-activated receptor gamma (PPARG)-mediated mechanisms." Thesis, 2009. http://hdl.handle.net/2440/61509.
Full textAbstract:
Across the world more women of childbearing age are becoming overweight and obese. Although
overweight women have similar co-morbidity and stigmata as men they also experience problems
specific to their gender. In particular, there is significant evidence that overweight and obese women
require a longer time to successfully conceive, suggesting influence of bodyweight and adipose tissue
mass upon the events surrounding conception.
This thesis investigated the interaction between diet-induced obesity and female reproductive function.
To achieve this, the influence of maternal obesity-induced insulin resistance on ovulation and oocyte
health, as indicated by subsequent embryonic developmental competence was determined.
Obesity adversely affects many aspects of health, and rodent models of diet-induced obesity are
commonly used to investigate these consequences. However the impact of strain and genetic
background on phenotypic response to diet, particularly in females, has not been systematically defined.
We therefore characterised female metabolic responses of five different strains of laboratory mouse
(Swiss, Balb/c, C57BL/6, CBA/CaH and 129T2Sv/Ems) to a “Western” high fat diet (22% fat, 0.15%
cholesterol) and matched control diet (6% fat, 0% cholesterol). After 16 weeks of diet exposure the
development and extent of hyperglycaemia, hyperinsulinaemia, insulin resistance, dyslipidaemia, and
markers of chronically inflamed adipose tissue depots varied profoundly across the different strains.
To then determine if a perturbed metabolic profile triggers female infertility, these female mice were
mated with strain matched, non-obese males, and zygotes extracted from the reproductive tract
immediately following fertilization. Despite strain-dependent variation in susceptibility to the
development of obesity, dyslipidaemia and insulin resistance, all mice investigated exhibit some degree
of impaired reproductive potential following exposure to a high fat diet. We documented alteration to
ovulation incidence and rate, fertilization, early embryo development to the blastocyst stage, and
blastomere differentiation into the inner cell mass and trophectoderm cell lineages.
The nature of obesity-induced perturbation of female reproductive processes was more closely
examined using statistical modelling which identified the specific metabolic parameters that were
strongly associated with reproductive defects. These associations were consistent across the range of
genetic backgrounds assessed and highlighted key mediators of this interaction, in particular, insulin
resistance.
To determine if ovarian gene products already implicated in other reproductive outcomes are
differentially regulated under conditions of obesity, ovarian mRNA collected at the pro-estrous (preovulatory)
stage of the reproductive cycle was applied to microarray slides developed through
Suppressive Subtractive Hybridization. Two different gene chips that were enriched for ovarian genes
were used. A number of genes were minimally regulated, and there was lack of significant validation in
subsequent, and larger, sample cohorts. These findings have provided substantial technical information,
and new experimental designs that overcome the current limitations have been established to obtain
more informative data.
The role that insulin resistance plays in folliculogenesis and the development of oocyte developmental
competence was more closely investigated. Hyperinsulinemia can interfere directly with ovarian cell
function or be indirectly associated with other hormonal conditions detrimental to optimal fertility. To
reverse the effects of obesity/hyperinsulinemia and identify the signalling pathways responsible for
disruption of pre-implantation events, obese female mice were treated for 4 days prior to mating with
three different insulin-sensitizing and plasma glucose-reducing pharmaceuticals: glucose and lipidlowering
AMP Kinase activator, AICAR, 30mg/kg/day; IκK inhibitor that reverses insulin resistance,
sodium salicylate, 50mg/kg/day; or Peroxisome Proliferator-Activated Receptor Gamma (PPARG)
agonist rosiglitazone, 10mg/kg/day. AICAR or sodium salicylate treatment did not have significant
effects on the reproductive parameters examined. However, embryonic development to the blastocyst
stage was significantly improved when diet-induced obese mice were treated with rosiglitazone,
effectively repairing development rates. Rosiglitazone also normalized obesity-associated abnormal
blastomere allocation to the inner cell mass. Such improvements to oocyte quality were coupled with
weight loss, improved glucose metabolism and changes in ovarian mRNA expression of PPARGregulated
cholesterol transporters.
Overall, this thesis has demonstrated for the first time a link between maternal obesity and the ovarian
follicle can impede oocyte health and developmental potential. As a result, the oocyte released at
ovulation expresses impaired developmental competence following to conception. Key cellular
pathways have been identified in this relationship, specifically PPARG-directed cell responses.Thesis (Ph.D.) - University of Adelaide, School of Paediatrics and Reproductive Health, 2009.
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Frank, Laura Alice. "The role of the hexosamine biosynthesis pathway and β-O-linked glycosylation in determining oocyte developmental competence." Thesis, 2012. http://hdl.handle.net/2440/96463.
Full textAbstract:
Maternal diabetes and conditions such as obesity in which blood glucose levels are elevated are associated with reduced fertility and poor pregnancy outcomes. Many studies have examined the effects of hyperglycaemia on the early embryo and fetus; however, it is becoming increasingly evident that the peri-conceptual environment surrounding the oocyte has a significant impact on developmental competence and the long-term health of offspring. In this thesis, I aimed to investigate the role of the hexosamine biosynthesis pathway (HBP) in oocyte developmental competence. The HBP is a glucose-metabolising pathway which can also be upregulated by glucosamine, a potent hyperglycaemic mimetic which enters the HBP downstream of the rate-limiting enzyme. The HBP produces uridine diphosphate-N acetylglucosamine, which can be used for the β-O-linked glycosylation (O-GlcNAcylation) of proteins, regulating their function in a similar manner to phosphorylation. Firstly I established the effect of hyper- and hypo-glycaemic conditions during in vitro maturation (IVM) of mouse cumulus-oocyte complexes (COCs) on a range of measures associated with oocyte developmental competence, including cumulus expansion, meiotic maturation, cleavage and blastocyst development rates. A low (1 mM) glucose concentration achieved optimal oocyte competence, and glucose supplementation during only the first hour of IVM was necessary and sufficient to support oocyte maturation and embryo development to the blastocyst stage. Glucosamine was able to substitute for glucose during this first hour. In the absence of glucose throughout IVM, glucosamine was not able to increase developmental competence, and at higher concentrations (2.5 and 5 mM) had a detrimental effect on these outcomes. These experiments underscored the importance of the other glucose metabolic pathways, during COC maturation, and supported the concept that excess flux through the HBP has detrimental consequences. Using Western blots and immunohistochemistry, it was shown that both glucosamine and high glucose levels induced an increase in total O-GlcNAcylation in COCs, which was reduced in the presence of an inhibitor of the β-O-linked glycosyltransferase enzyme. Several specific proteins were identified using mass spectrometry as potential targets of O-GlcNAcylation in COCs, including heat-shock protein 90 (HSP90, both α and β isoforms). While glucosamine treatment of COCs significantly decreased blastocyst development rate, inhibiting HSP90 with 17-allylamino-17-demethoxygeldanamycin during IVM in the presence of glucosamine recovered blastocyst rates to control levels. This effect was not due to an increase in overall HSP90 levels, since inhibiting HSP90 in control COCs did not affect blastocyst rate. These results suggest O-GlcNacylated HSP90 has an aberrant function in the COC. This study is the first to examine in detail O-GlcNAcylation levels in the COC, and their correlation to oocyte developmental competence. HSP90 was identified as a potential target of O-GlcNAcylation in the COC, and subsequently shown to mediate oocyte developmental competence. This research is significant because of the increasing numbers of women wishing to become pregnant who have high blood glucose levels due to diabetes, obesity or poor diet. I have generated critically needed knowledge towards understanding how these lifestyle factors affect fertility and identifying possible avenues for new therapies.Thesis (Ph.D.) -- University of Adelaide, School of Paediatrics and Reproductive Health, 2012
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"Effects of follicular aging and duration of superstimulation on oocyte competence and granulosa cell gene expression in cattle." Thesis, 2013. http://hdl.handle.net/10388/ETD-2013-06-1110.
Full textAbstract:
A prolonged growth phase of the ovulatory follicle results in follicular aging. Whether follicular aging is detrimental or beneficial to oocyte competence is not fully known. The objective of this thesis is to investigate the effects of follicular aging on oocyte competence and granulosa cell gene expression in cattle. Four sets of experiments were designed to address the objective. The following hypotheses were tested during the course of these studies: 1) oocyte competence will improve by the longer growing phase but will be adversely affected by FSH starvation, 2) follicles that undergo superstimulation will have different gene expression than dominant follicles from a natural cycle, 3) extending the superstimulation protocol by 3 days will allow follicles to mature better and 4) markers of maturity, cellular health and survival will be turned off by FSH starvation.
The objective of the first study (Chapter 3) was to determine the effects of extending the length of superstimulation and follicular aging on oocyte competence by in vitro embryo production. Multiple follicles were allowed to grow for 4 (Short FSH) or 7 days (Long FSH) under the treatment of 8 or 14 injections of FSH (at 12-hour intervals), respectively. Multiple follicles in the FSH starvation group were allowed to grow for 7 days but FSH was provided for only the first 4 days of superstimulation. Extending the duration of follicular growth by superstimulation resulted in a greater number of ≥9 mm follicles and in 2.5 more transferable embryos per animal (morulae+blastocysts) at Day 9 of in vitro embryo culture. The FSH starvation resulted in a greater proportion of poor quality oocytes lower cleavage rate and lower embryonic development.
Microarray analysis was used to assess the effect of superstimulation (Chapter 4), follicular aging (Chapter 5) and FSH starvation (Chapter 6) on the gene expression profile of superstimulated granulosa cells. Gene expression of granulosa cells from the post-LH preovulatory dominant follicle was compared (Chapter 4) with those from follicles of the same status after a standard 4-day superstimulation (same protocol as Short FSH group from Chapter 3). A total of 190 genes were down-regulated and 280 genes were upregulated in the superstimulated group when compared with the reference (non-superstimulated control). Data analysis showed that superstimulated follicles are still in a growing phase compared to untreated dominant follicles (most of the upregulated genes are related to matrix remodeling due to tissue proliferation) and did not respond to LH properly (down regulation of LH gene markers). Four-day superstimulation also disturbed genes related to angiogenesis and activated oxidative stress response genes. Extending the superstimulation protocol (7 days; same protocol as Long FSH from Chapter 3) allowed more time for follicles to leave the growing stage and properly respond to LH surge (most of the upregulated genes in the Long FSH group are markers of post LH surge) when compared to the standard 4 day superstimulation protocol (Short FSH; reference group) (Chapter 5). Moreover, the follicles from Long FSH show proximity to ovulation. The continuous FSH support during the extended superstimulation protocol is crucial for follicular health since FSH starvation disturbed genes markers of oocyte quality and embryo development (Chapter 6). Granulosa cells that underwent FSH starvation do not respond to LH surge, which could be detrimental to ovulation (Chapter 6).
Therefore, follicles from Short FSH are delayed in maturation and differentiation but the oocyte competence is not compromised. Extending superstimulation protocol by 3 d enhanced the ovarian response to FSH treatment and allowed more time for follicles to mature and properly respond to the LH stimulus. A period of FSH starvation after superstimulatory treatment compromised follicular health, ability to respond to LH and ovulate, oocyte quality and the fertilization process.
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Thomas, Rebecca Elizabeth. "Differential effects of specific phosphodiesterase isoenzyme inhibitors on bovine oocyte meiotic maturation, gap junctional communication, and developmental competence / Rebecca Thomas." 2003. http://hdl.handle.net/2440/22039.
Full textAbstract:
"December, 2003"Bibliography: leaves 153-161.
xii, 191, [20] leaves : ill. ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
"The work presented in this thesis demonstrates that the exploitation of subtype-specific PDE inhibitors is a powerful experimental approach to study the oocyte and surrounding cumulus cells in separation, and to investigate the functions of cAMP in the two follicular compartments. The successful use of specific PDE isoenzyme inhibitors will prove important in the development of a clearer and more defined understanding of the fundamental mechanisms of regulating mammalian oocyte maturation." --p. 150.
Thesis (Ph.D.)--University of Adelaide, Dept. of Obstetrics and Gynaecology, 2004?
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Thomas, Rebecca Elizabeth. "Differential effects of specific phosphodiesterase isoenzyme inhibitors on bovine oocyte meiotic maturation, gap junctional communication, and developmental competence / Rebecca Thomas." Thesis, 2003. http://hdl.handle.net/2440/22039.
Full textAbstract:
"December, 2003"Bibliography: leaves 153-161.
xii, 191, [20] leaves : ill. ; 30 cm.
"The work presented in this thesis demonstrates that the exploitation of subtype-specific PDE inhibitors is a powerful experimental approach to study the oocyte and surrounding cumulus cells in separation, and to investigate the functions of cAMP in the two follicular compartments. The successful use of specific PDE isoenzyme inhibitors will prove important in the development of a clearer and more defined understanding of the fundamental mechanisms of regulating mammalian oocyte maturation." --p. 150.
Thesis (Ph.D.)--University of Adelaide, Dept. of Obstetrics and Gynaecology, 2004?
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Pešanová, Denisa. "Transkripční aktivity genů, charakterizujících vývojově kompetentní cytoplazmu oocytů skotu." Master's thesis, 2013. http://www.nusl.cz/ntk/nusl-321110.
Full textAbstract:
4 Abstract The antral follicle provides a specialized microenvironment or niche, which is necessary for production of high quality oocyte. The developmental competence of bovine oocyte is influenced by the follicle size. Oocytes originated from medium or larger follicles (≥6 mm) have greater developmental competence (ability to develop to the blastocyst stage). The changes in cytoplasmic factors, for example mRNAs, could explain differences in oocyte developmental potential. Using Bovine Oligonucleotide microarrays the differences in gene expression profiles of oocytes at germinal vesicle and MII stages from medium (MF, 6-10 mm) or small (SF, 2-5 mm) follicles were characterized. The aim was to find differencies between oocytes diverse developmental competence. The expression fold change between the two experimental groups was in 61 genes. Subsets of 15 differentially expressed genes were validated by quantitative RT-PCR. Before maturation, significant differences were confirmed at the level of ATP5C1, MAP3K13, MTRF1L, TAF1A and UBL5. Subpopulations of oocytes were classified according to atresia of cumulus cells and follicle size. We determined the level of 12 individual transcripts after maturation. ATP5F1 remained stable in all experimental groups of oocytes. The level of BRD7 transcript remained stable...