Tesi sul tema "Rabbits Anatomy"

Lesões da cartilagem articular podem ser tratadas por meio de cirurgia de transplante osteocondral autólogo. Esta cirurgia baseia-se na colocação de cilindros osteocondrais em áreas de lesão da cartilagem articular. O objetivo principal deste estudo foi avaliar as consequências histológicas das variações de posicionamento de enxertos osteocondrais cilíndricos: no mesmo nível e desnivelados (salientes ou profundos) em relação à superfície articular. Neste estudo, foram utilizados vinte coelhos fêmeos adultas, albinos, da raça Nova Zelândia. Defeitos cilíndricos osteocondrais de três milímetros de diâmetro e três milímetros de profundidade foram tratados por esta técnica cirúrgica. Os enxertos foram posicionados aleatoriamente em três formas: ao mesmo nível da superfície articular, profundos e salientes em relação à superfície articular. Realizou-se análise macroscópica e histológica após doze semanas de evolução. Como resultados, observamos que as avaliações macroscópicas e histológicas mostraram diferenças entre os três tipos de posicionamentos. Os enxertos posicionados ao mesmo nível da superfície articular obtiveram melhores resultados. Os resultados dos enxertos posicionados salientes à superfície articular foram melhores do que os dos enxertos posicionados profundos em relação ao nível articular
The treatment of symptomatic chondral lesions aims to restore function similar to that observed before the lesion. Autologous osteochondral transplantation is a surgical procedure that consists of filling a full-thickness articular cartilage defect with normal cartilage. The main objective of this study was to evaluate the histological consequences of the positional incompatibilities of cylindrical osteochondral grafts placed either flush with the articular surface or protruding/recessed. Two experimental groups of 10 rabbits each were randomly established regarding the positioning of the osteochondral autograft: in 1 knee, the graft was implanted either protruding or recessed with respect to the articular surface, and the graft was implanted at the level of the articular surface in the other graft. The protruding graft was placed 2 mm above the level of the articular cartilage, and the recessed graft was placed 1 mm below the level of the articular cartilage. After euthanasia, the articular cartilage was macroscopically evaluated according to the scale published by Goebel et al. and histologically evaluated by haematoxylin-eosin and safranin-O staining according to the International Cartilage Repair Society (ICRS) II classification. The evaluated parameters did not significantly differ between the protruding and recessed groups, whereas flush positioning resulted in better scores according to the Goebel et al. scale and the ICRS II classification. Recessed and protruding positioning relative to the articular surface did not produce different results

O objetivo deste estudo foi avaliar se a injeção intra-articular em altas doses de ácido hialurônico, imediatamente após o trauma, pode reduzir a apoptose de condrócitos. Para cumprir este objetivo foi desenvolvido um estudo experimental com 40 joelhos de coelhos adultos. Os animais foram anestesiados e, em seguida, cada joelho sofreu três contusões com um bloco de 1 kg, solto por meio de um cilindro, a 1 metro de altura. Logo após as contusões, foram administrados, no mesmo coelho, 2 ml de ácido hialurônico em um joelho e 2 ml de solução salina no outro. Desta forma, obteve-se uma intervenção pareada, com melhora do poder estatístico do estudo. As doses foram repetidas a cada 3 ou 4 dias por 30 dias. Os coelhos foram mantidos no mesmo ambiente sob controle de temperatura, de atividades diárias e de alimentação. Após 30 dias, os animais foram abatidos e, por meio de artrotomia, foram realizadas as coletas da cartilagem do côndilo femoral medial e da tróclea de cada joelho. As peças foram preparadas para análise em microscopia óptica e coloração por TUNEL. Os indivíduos envolvidos no preparo e análise das peças não tiveram qualquer tipo de informação a respeito do experimento. A análise estatística foi feita pelo Teste t-student para dados pareados na comparação entre o grupo ácido hialurônico (AH) e o grupo controle. Foram analisados um total de 36 joelhos e obteve-se uma redução significativa (p<0,001) na taxa de apoptose de 68,01% (+ 19,73) do grupo controle para 53,52% (+ 18,09) do grupo AH. Diante dos resultados, concluiu-se que a injeção intra-articular de altas doses de ácido hialurônico, iniciando imediatamente após o trauma, reduz as taxas de apoptose (pós-traumática) de condrócitos de coelhos
The aim of this study was to assess whether intra-articular injection of high doses of hyaluronic acid immediately after trauma, can reduce apoptosis of chondrocytes. We have developed an experimental study with forty knees of adult rabbits. Animals were anesthetized and each one had had three knee injuries with a block of 1kg, released through a cylinder, 1 meter tall. After the bruises, 2ml of hyaluronic acid were injected in one knee and 2ml saline in the other. Doses were repeated each 3 or 4 days during 30 days. Rabbits were kept in the same environment under controlled temperature, daily activities and meals. Thirty days later, animals have been sacrificed. The cartilage of the medial femoral condyle and trochlea of each knee was retrieved with a scalpel by artrothomy. Specimens were prepared for optical microscopy and TUNEL staining. No information about the experiment was given to individuals who were involved in the preparation and analysis of the slides. Statistical analysis was performed by Students t test for paired data when comparing a group of hyaluronic acid (HA) and control group. We have analyzed a total of 36 knees and have obtained a significant reduction (p <0.001) in apoptosis rate of 68.01% (+ 19.73) for the control group 53.52% (+ 18.09) in the HA group. We conclude that the intraarticular injection of high doses of hyaluronic acid starting immediately after trauma, reduces impact-induced chondrocytes apoptosis rates in rabbits

A cartilagem articular, por sua natureza avascular, apresenta uma capacidade limitada de regeneração. Uma abordagem terapêutica para o tratamento de defeitos da cartilagem consiste na utilização de células ou tecidos aplicados ao local da lesão. O objetivo deste estudo foi avaliar o efeito da aplicação de centrifugado de medula óssea autóloga em lesões osteocondrais no joelho de coelhos, em comparação com um grupo controle de lesões osteocondrais sem preenchimento, analisando o comportamento histológico destes grupos em função do tempo. Foram utilizados doze coelhos da raça Nova Zelândia, albinos, machos, adultos, submetidos a uma lesão osteocondral, de 4 mm de diâmetro e 3 mm de profundidade, em ambos os joelhos, na região da tróclea femoral. Nos joelhos direitos, que constituíram o Grupo Estudo, o defeito osteocondral foi preenchido por um coágulo de células mesenquimais, obtidas por centrifugação de um aspirado da medula óssea e selado com cola de fibrina. Nos joelhos esquerdos, que constituíram o Grupo Controle, o defeito osteocondral não recebeu qualquer preenchimento. Os animais foram divididos em três grupos de quatro coelhos, estudados após oito, 16 e 24 semanas. Os resultados foram descritos com base em uma escala de pontuação histológica que avaliou a morfologia celular, a reconstrução do osso subcondral, o aspecto da matriz, o preenchimento do defeito, a regularidade da superfície e a conexão das margens. A análise estatística foi realizada pelo Teste t-student para dados pareados na comparação entre Grupo Estudo e Grupo Controle. Para as comparações através do fator temporal, utilizou-se o Teste ANOVA one way. Com 5% de confiança, rejeitou-se a hipótese de igualdade entre os Grupos Estudo e Controle. Notou-se uma distância decrescente entre os escores dos Grupos Estudo e Controle com o aumento do tempo, bem como uma tendência crescente do valor da escala para o Grupo Controle. Concluiu-se que a aplicação de centrifugado de medula óssea em defeitos osteocondrais no joelho de coelhos mostrou melhor resultado na avaliação histológica, em comparação ao Grupo Controle. Analisando a evolução dos grupos através do tempo, houve uma aproximação de seus escores histológicos, sobretudo pelo aumento observado no Grupo Controle
The articular cartilage, due to its avascular nature, presents a limited regeneration capacity. A therapeutical approach to the treatment of cartilage defects consists of the utilization of cells or tissues applied to the lesion site. The aim of this study was to evaluate the effect of applying autologous bone marrow centrifuged in osteochondral lesions in the knees of rabbits, compared to a control group of osteochondral lesions without any filling, analyzing the behavior of these groups in terms of time. Twelve adult albino male New Zealand rabbits were used being submitted to an osteochondral lesion of 4 mm in diameter and 3 mm deep in both knees, at the femoral trochlea area. On the right knees, which comprised the Study Group, the osteochondral defect was filled by a clot of mesenchymal cells, obtained by centrifugation of an aspirate from bone marrow and sealed with fibrin glue. On the left knees, which comprised the Control Group, the osteochondral defect did not get any filling. The animals were divided into 3 groups of 4 rabbits, and studied after eight, 16 and 24 weeks. The results were described based on a histological grading scale which took into account the cell morphology, the subchondral bone reconstruction, the matrix staining, the filling of the defect, the surface regularity and the bonding of the edges. The statistical analysis was made by the t-student Test for paired data in the comparison between the Study Group and the Control Group. For the comparisons made by the time factor, it was used the ANOVA Test one way. With 5% level of confidence, the hypothesis of equality between the Study and Control Groups was rejected. It was observed a decreasing distance between scores of the Study and Control Groups as time increased, as well as an increasing tendency of the scale value for the Control Group. It was concluded that the application of autologous bone marrow centrifuged in osteochondral defects in the knees of rabbits showed better result in histological evaluation, in comparison to the Control Group. By analyzing the evolution of the groups through time, there was an approach of their histological scores, especially by the increase observed in the Control Group

Desde o início de 1990, a enxertia de gordura na prega vocal é descrita como um método para reparar a insuficiência glótica. O objetivo deste estudo é avaliar os efeitos da aplicação tópica de mitomicina-C no processo cicatricial de enxertos autólogos de gorduras inseridos em pregas vocais de coelhos através da medida da deposição de colágeno. Vinte e oito coelhos foram submetidos a enxertia de gordura em ambas pregas vocais. As pregas vocais direitas recebeu previamente a aplicação tópica de mitomicina-C (0,4mg/ml) durante cinco minutos enquanto que as pregas vocais esquerdas formavam o grupo controle (sem mitomicina-C). Quatro grupos com 6 coelhos cada foram sacrificados com 7, 14, 30 e 90 dias após a cirurgia de enxertia. As pregas vocais foram removidas para estudo histológico com a intenção de quantificar a deposição de colágeno através da coloração por Picrossírius Red sob microscopia polarizada. A deposição de colágeno foi menor em todos os grupos de pregas vocais que receberam aplicação tópica de mitomicina-C quando comparada com as pregas vocais do grupo controle. No presente estudo, a aplicação tópica de mitomicina-C antes da enxertia de gordura reduziu significativamente a deposição de colágeno (p = 0,05).
Since the early 1990s, fat implantation in the vocal fold is described as a method of repairing glottal insufficiency. The aim of this study was to evaluate the effect of topical application of mitomycin in the healing process with collagen deposition measurement around of autologous fat implants inserted in rabbits vocal folds. Twenty-eight rabbits were submitted to a fat implant in the both vocal folds. The right vocal folds received previously topical application of mitomycin (0,4mg/ml) for five minutes and the left vocal folds were the control group (without mitomycin). Four groups of 6 rabbits each were sacrificed 7, 14, 30 and 90 days after the implantation. The samples of the vocal folds were collected for histological analysis with the purpose of quantifying the collagen deposition by Picrosirius Red stain under polarization microscopy. The collagen deposition was lower in all groups of vocal folds with topical application of mitomycin than in control groups. In the present study, the topical application of mitomycin before the fat grafts reduced significantly the collagen deposition (p = 0,05).

Lactational anoestrus and anovulation place limitations on the economic and biological efficiency of the three main domestic farm species ie cow, pig and sheep by reducing reproductive efficiency. The factors of Remating Interval, Nutrition and Suckling have been shown to influence fertility during lactation in these species. The objective of the present study was to examine the effects of these factors on fertility and identify the mechanisms by which they act, using the lactating domestic rabbit as an experimental model and so provide information which may help overcome the obstacles preventing concurrent pregnancy and lactation in the domestic farm species. Experiment 1 provided data on the fertility of primiparous crossbred lactating does in the immediate postpartum period. This information was used to decide on which day postpartum does should be remated in subsequent experiments. Sixty-four does each suckling 6 pups were mated on day 1 (N = 17), 2 (N = 17), 3 (N = 15) or 4 (N = 15) postpartum (where day 0 = the day of parturition) and killed on day 10 postcoitum (where day 0 = the day of mating) to assess fertility. Overall fertility levels were high during this period. There were no significant differences between does remated on day 1- 4 postpartum in their mating response (percentage of those does tested for mating, which mated) and, overall this was 97%, ovulation response (percentage of those does mating, which ovulated), overall 77%, implantation response (proportion of those does ovulating, which implanted ova), overall 83%, implantation rate, overall 8.7 or pre-implantation mortality (%), overall 24%. Ovulation rate was significantly increased in does mated on day 3 (13.3) and 4 (13.1) compared with those on day 1 (10.2) (P 0.05) and 2 (9.6) (P 0.01) postpartum. From these results day 1 postpartum remating was found to result in the highest level of absolute fertility (ie by multiplication of the estimated pregnancy rates (the percentage of does implanting ova of those mated) of' 82%, 60%, 60% and 53% with the implantation rate 7.9, 8.1, 9.4 and 9.6 of does mated on day 1 (N = 17) , 2 (N = 15), 3 (N = 15) and 4 (N = 15) postpartum respectively, giving a total of 111, 73, 85 and 77 pups on day 1, 2, 3 and 4 respectively) during this period postpartum and was therefore used in future experiments concerning the remating interval. In Experiment 2, the effects of the remating interval and nutrition on the fertility of lactating crossbred does was examined. Eighty-six does each suckling six pups were remated on either day 1 or 14 postpartum and offered diets with digestible energy (D.E.) contents of 8.5 or 15.4 M.J./ kg D.M. and digestible crude protein contents (D.C.P.) of 129 or 227 g/kg D.M. and which were otherwise nutritionally adequate for lactating does. The experiment was carried out over three consecutive lactations and does were killed at selected times in each lactation to assess fertility and body composition. Diet had no effect on any aspect of fertility, while in contrast the remating interval was shown to have a significant effect. Does remated on day 1 had a significantly greater ovulation response in the first (82% vs 63%, P 0.10) and second (100% vs 77%, P 0.05) lactation compared with those mated on day 14 postpartum. Pregnancy rate was also significantly greater in does remated on day 1 in the first (76% vs 51%, P 0.05) and the second (100% vs 67%, P 0.01) lactation compared with those mated on day 14 postpartum. There were no differences in pre or post-implantation mortality between does remated on day 1 and 14 postpartum and therefore pregnancy rate was determined by the initial ovulation response. Litter size at term was found to be related to the initial ovulation rate and both were greater in does remated on day 14 compared to day 1 postpartum. This reached significance for litter size at term in the first lactation (7.8: day 1 vs 10.1: day 14, P 0.01) and ovulation rate in the second lactation, which was 12.4 for does remated on day 1 and 17.8 for those remated on day 14 postpartum (P 0.01). There was no significant difference in the body composition of pregnant does on the various treatment combinations over the course of the experiment or in lactation performance between does which were pregnant and those which were not. Experiment 3 was undertaken to confirm the effects of the remating interval on fertility observed in does on Experiment 2 and also to record measures of doe lactation performance to assess if they could be related with the effects of this factor.

Dissertação de Mestrado Integrado em Medicina Veterinária
O vírus da doença hemorrágica dos coelhos de tipo 2 (RHDV2) foi detetado em Portugal pela primeira vez, em 2012, e encontra-se atualmente disseminado em todo o território nacional incluindo Madeira, Açores e Berlengas. O papel ecológico e económico do coelho-bravo, aliado à sua importância para os níveis tróficos superiores, levou a que o Governo Português ativasse em 2017 um plano para controlo desta doença (Despacho 4757/2017 de 31 de Maio). Este trabalho teve como objetivo estabelecer padrões de lesão histopatológica nos principais órgãos afetados (fígado, pulmão, baço, duodeno, coração, entre outros) durante a infeção por RHDV2 e relacioná-los com os padrões de distribuição de cargas virais (medidos através dos valores de Cq obtidos por RT-qPCR) em sete matrizes (fígado, baço, duodeno, fezes, rim, pulmão e ventrículo esquerdo). Todos os coelhos-bravos investigados (n=49), foram obtidos no âmbito deste estudo, durante suspeitas de surtos de DHV, sendo oriundos de vários locais. No grupo dos animais não vacinados, o diagnóstico virológico e histopatológico raramente suscitou dúvidas e não foram encontradas lesões macro e microscópicas diferentes entre os coelhos jovens e os animais adultos. No entanto foi observada uma diminuição significativa das cargas virais nos órgãos dos animais vacinados para RHDV2 quando comparados com os animais não vacinados, tal como já descrito na literatura. Em alguns animais vacinados, foi difícil detetar o vírus por métodos moleculares apesar da presença de graves lesões histopatológicas compatíveis com DHV. No caso dos animais vacinados, a valores de Cq tendencialmente maiores, correspondeu uma menor prevalência do padrão lesional hepático mais grave. Contrariamente, nos animais não vacinados, foram encontrados valores de Cq tendencialmente mais baixos no fígado (maiores cargas virais), correspondendo a um padrão lesional mais grave. Os dados obtidos indicam também que o fígado não é o órgão de eleição para diagnóstico de RHDV2 em animais vacinados, já que o pulmão foi a matriz onde o vírus foi mais detetado. Curiosamente, o ventrículo esquerdo apresentou-se como a matriz com maior percentagem de positividade em todos os grupos pelo que a pertinência da sua utilização sistemática no diagnóstico molecular, deve ser investigada. Foi ainda realizada a pesquisa de RHDV2 em outras espécies simpátricas: lebre ibérica (n=2), toirão (n=1), texugo (n=1), sacarrabos (n=1), roedores (n=18), pardalcomum (n=1), insetos (n> 2568) e ixodídeos (n=28)). Foi detetado RNA viral no pulmão de um toirão, no fígado e ventrículo esquerdo de uma lebre, nas fezes do pardal comum, e em 3 famílias de insetos (Ceratopogonidae, Staphylinidae e Simuliidae). Este trabalho trouxe novos dados para a compreensão da interface patogenia-diagnóstico e para a compreensão da eco-epidemiologia da DHV
ABSTRACT - Anatomo-histopathological analysis and molecular diagnosis of Viral Haemorrhagic Disease in wild rabbit - Rabbit haemorrhagic disease virus 2 (RHDV2) was detected in Portugal for the first time in 2012. It is currently widespread in the continent and islands (Azores, Madeira and Berlengas). The ecological and economic role of the wild rabbit and its crucial importance for the higher trophic levels, led the Portuguese Government to activate, in 2017, an action plan to control this disease (Dispatch 4757/2017 of 31 May). This work aimed to establish patterns of histopathological lesions in the organs affected during infection (liver, lung, spleen, thymus, duodenum, heart among others) and to relate them to the viral load distribution patterns, measured by the Cq values obtained with a RHDV2-specific RT-qPCR, in seven biological matrices (liver, spleen, duodenum, faeces, kidney, lung and left ventricle). All the wild rabbits investigated (n = 49) were obtained within the scope of this study and originated from several locations (mainly two wild-rabbit farms with management conditions and different purposes) during suspected outbreaks of haemorrhagic viral disease. In the group of unvaccinated animals, the virological and histopathological diagnosis rarely raised doubts and no different macro and microscopic lesions were found between young rabbits and adult animals No differences in the macro and microscopic lesions were found between young and adult rabbits but a significant decrease in the viral loads of organs was observed in RHDV2 vaccinated rabbits, when compared to non-vaccinated rabbits, as described before in the literature. In some animals that had been vaccinated, it was difficult to detect the virus by molecular methods, although severe histopathological lesions were identified. For the vaccinated group, the increase in the Cq values tended to be accompanied by a more variable lesional pattern, with the more severe ones being less prevalent. In the liver of nonvaccinated rabbits, for example, as Cq values decreased (corresponding to higher viral charges), more severe lesional patterns were observed. Our data indicate that the liver is not the organ of choice for RHDV2 molecular diagnosis in vaccinated animals, since the virus was more often detected in the lungs. Interestingly, the left ventricle showed the highest percentage of positivity in all groups, so the relevance of its systematic use for diagnosis should be considered and investigated. RHDV2 was also investigated in other sympatric species, such as Iberian hare (n=2), toad (n=1), badger (n=1), rodents (n=18), common sparrow (n=1), insects (n>2568) and ixodids (n=38). Viral RNA was detected in the lung of a toad, in the liver and heart of a hare in the faeces of the common sparrow, and in 3 families of insects (Ceratopogonidae, Staphylinidae and Simuliidae). This work brought new insights to the pathogeny-diagnosis interface and to the comprehension of the disease eco-epidemiology.
Financiado por: Fundo Florestal Permanente
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The adult respiratory distress syndrome (ARDS) is a life threatening complication with a high mortality rate which occurs in patients in a variety of situations. The diverse aetiologies of the syndrome have led to difficulties in defining and diagnosing those patients suffering from ARDS.This thesis describes the induction of pulmonary damage in two animal species, using a number of stimuli in an attempt to mimic the histological damage seen at autopsy in patients who have died of the adult respiratory distress syndrome. The intravenous administration of oleic acid in both mouse and rabbit induced fat embolism and lung pathology similar to that seen in some ARDS patients. In the rabbit these histological changes have been correlated with physiological measurements made during the course of the damage. In the anaesthetised, spontaneously breathing rabbit gram-negative scepticaemia, a major precursor of ARDS in humans, was induced by the intravenous administration of live E.Coli bateria. Physiological measurements relevant to pulmonary gas exchange efficiency were made during the course of the infusion of bacteria and for several hours after. The lung damage induced by gram-negative sepsis in the rabbit has been compared to that induced by oleic acid emoblism, E. Coli endotoxin and phorbol myristate acetate. The role of the polymorphonuclear leucocyte in the pathogenesis of lung damage induced by several of the stimuli used in these experiments has been studied in both the mouse and the rabbit models described in this thesis.

Vários materiais têm sido injetados ou inseridos nas pregas vocais na tentativa de solucionar a incompetência ou insuficiência glótica. Contudo, poucos são os estudos que avaliam o processo cicatricial decorrente da enxertia destes materiais. O objetivo desta pesquisa foi quantificar e comparar as fibras colágenas no músculo vocal das laringes dos coelhos que foram submetidos a enxerto unilateral de gordura ou fáscia muscular com a prega vocal contra-lateral, que foi submetida ao mesmo procedimento, com exceção da enxertia. Estudamos 24 coelhos, divididos em dois grupos com 12 coelhos em cada um. No primeiro grupo, denominado F (Fáscia), os coelhos foram submetidos à inserção de enxerto de fáscia lata autóloga na prega vocal direita. No outro grupo, denominado G (Gordura), os coelhos foram submetidos a implante de gordura autóloga \"em bloco\" também na prega vocal direita. Todos os coelhos foram também submetidos ao mesmo procedimento na prega vocal esquerda, com exceção da colocação do enxerto. A prega vocal esquerda, desta forma, constituiu o \"controle\" para cada coelho. Metade dos coelhos, de cada um dos grupos (F e G), foi sacrificada após 90 dias do procedimento cirúrgico. A outra metade dos coelhos dos grupos G e F foi sacrificada após 180 dias do procedimento cirúrgico. As laringes foram removidas e as pregas vocais, direita e esquerda, foram preparadas histologicamente. Os cortes corados pelo método da picrosírius-polarização foram utilizados para a visualização e análise das fibras colágenas. O colágeno foi analisado morfometricamente através do método da Picrossírius-polarização com a utilização do software Image Pro Plus. Houve aumento do colágeno em todos grupos enxertados quando comparados com o grupo controle. A concentração do colágeno encontrada nos coelhos submetidos a enxerto de gordura foi significativamente maior quando comparados à concentração do colágeno nos coelhos submetidos a enxerto de fáscia muscular, tanto com 90 quanto com 180 dias. A enxertia de gordura e fáscia lata na prega vocal de coelho promoveu maior deposição de colágeno do que no grupo controle, sendo mais exuberante na inserção de gordura
Several materials have been injected or inserted in the vocal fold, in attempt to solve glottic insufficiency. Nevertheless, there is just a few papers that evaluates the inflammatory process resulted from these materials incorporation. The objective of this study was to quantify and compare the collagen fibers in the vocal muscle of the larynx from the rabbits in which unilateral fat and muscular fascia were introduced, to the contralateral vocal fold, in which the same procedure have taken place, except be the grafting. Twenty four rabbits were used in this study, divided into two groups, 12 rabbits each. In the first group, named F (from Fascia), the rabbits underwent the insertion of fascia lata into the right vocal fold. In the other group, named G (from Grease), the rabbits underwent implantation of autologous fat \"en bloc\" in the right vocal fold, as well. All rabbits have undergone the same procedure in the left vocal fold, except for the graft insertion. The left vocal fold, therefore, formed the control group for each rabbit. Half the rabbits, form each group (F and G), was sacrificed after 90 days, while the other half was sacrificed after 180 days from the surgical procedure. The larynxes were removed and the vocal folds, right and left, were prepared for histology, using the method of picrosirius-polarization for the coloration. The collagen fibers in the samples were analyzed using a computer software called Image Pro Plus. An increasing of the collagen was found in all the groups in which grafts have been placed, when compared to the control group. The collagen density found in those rabbits which underwent fat insertion was significantly higher than in those with muscular fascia insertion, for both periods of 90 and 180 days, as well. Fat and muscular fascia insertion in rabbits vocal fold resulted in a higher collagen deposition, when compared to the control group, being