Desenvolvimento folicular ao longo do ciclo éstrico na cadela e gata
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2017
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Ao longo do ciclo éstrico estão presentes folículos ováricos em todas as fases de desenvolvimento, isto é, em quiescência, crescimento e atresia. No entanto, cada espécie tem a sua própria escala temporal de desenvolvimento, envolvendo processos como a proliferação e diferenciação das células foliculares. Contudo, o conhecimento sobre os mecanismos que regulam o desenvolvimento folicular é ainda fragmentário. O desvendar destes processos poderá contribuir para o desenvolvimento de novos métodos de controlo da fertilidade.
O objetivo do presente estudo consiste em determinar se a proliferação celular nos folículos ovários está relacionado com o recrutamento e desenvolvimento folicular, acompanhando a sua ocorrência ao longo do ciclo éstrico. Este trabalho foca-se ainda na comparação do desenvolvimento e recrutamento folicular entre cadelas e gatas, espécies que embora filogeneticamente afastadas, concentram forte interesse veterinário.
Foram recolhidos ovários de 13 cadelas e 11 gatas com idades compreendidas entre os 5 meses e 2 anos de idade, os quais foram agrupados de acordo com a fase do ciclo éstrico. A fase do ciclo éstrico foi determinada através da citologia vaginal, concentração plasmática de progesterona (P4) e observação histológica dos ovários. O estudo foi desenhado no sentido de utilizar a expressão do Antigénio Nuclear de Proliferação Celular (PCNA) como marcador de proliferação celular nos folículos ováricos.
Este estudo apresenta uma descrição detalhada do padrão de expressão de PCNA durante o desenvolvimento folicular nestas duas espécies, os resultados obtidos permitiram concluir que a proliferação celular varia consoante o desenvolvimento folicular e a fase do ciclo éstrico, tanto em cadelas como em gatas, havendo uma interação significativa entre estas duas variáveis. Neste contexto, a regulação da proliferação celular no folículo poderá ser uma via terapêutica para o controlo da fertilidade (estimulação ou contraceção). Contudo, este trabalho servirá essencialmente como base para estudos subsequentes que permitam desvendar melhor os processos fisiológicos que regulam a foliculogénese. Além disso, o presente trabalho e estágio contribuíram ainda para estabelecer e otimizar o protocolo de imunohistoquímica no laboratório de investigação da FMV-ULHT.
Throughout the cycle, ovarian follicles are present at all stages of development, in quiescence, growth, and atresia. However, each species has its own development timeline, involving processes such as proliferation and differentiation of follicular cells. However, the knowledge regarding the mechanisms that regulate follicular development is still fragmented and controversial. Thus, in order to develop novel fertility control therapeutic methods, it is fundamental to unfold the regulatory mechanisms behind follicle selection and growth. The aim of this study was to determine if ovarian follicles cell proliferation is related with follicle recruitment and development along the estrous cycle. This study also focuses on the folliculogenesis comparison between bitches and queen, species that although phylogenetically distant, concentrate strong veterinary interest. Ovaries were collected from 13 bitches and 11 queens with ages ranging from 5 months to 2 years old. Ovaries were grouped according to the animal estrous cycle phase. Estrous cycle phase was determined by vaginal cytology, plasma progesterone concentration (P4) and histological observation of the ovaries. The study was designed to use the expression of Proliferative Cell Nuclear Antigen (PCNA) as a marker of cell proliferation in ovarian follicles. This study presents a detailed description of PCNA expression pattern during follicular development in these two species, the results obtained allowed to conclude that cell proliferation varies according to follicular development and estrous cycle phase, both in bitches and queens, with both this variables having a significative interaction. In this context, the regulation of cell proliferation in the follicle may be a therapeutic route for fertility control (stimulation or contraception). However, this work will essentially serve as a basis for subsequent studies to better uncover the physiological processes that regulate folliculogenesis. In addition, the present work contributed to establish and optimize the immunohistochemical protocol in the FMV-ULHT research laboratory.
Throughout the cycle, ovarian follicles are present at all stages of development, in quiescence, growth, and atresia. However, each species has its own development timeline, involving processes such as proliferation and differentiation of follicular cells. However, the knowledge regarding the mechanisms that regulate follicular development is still fragmented and controversial. Thus, in order to develop novel fertility control therapeutic methods, it is fundamental to unfold the regulatory mechanisms behind follicle selection and growth. The aim of this study was to determine if ovarian follicles cell proliferation is related with follicle recruitment and development along the estrous cycle. This study also focuses on the folliculogenesis comparison between bitches and queen, species that although phylogenetically distant, concentrate strong veterinary interest. Ovaries were collected from 13 bitches and 11 queens with ages ranging from 5 months to 2 years old. Ovaries were grouped according to the animal estrous cycle phase. Estrous cycle phase was determined by vaginal cytology, plasma progesterone concentration (P4) and histological observation of the ovaries. The study was designed to use the expression of Proliferative Cell Nuclear Antigen (PCNA) as a marker of cell proliferation in ovarian follicles. This study presents a detailed description of PCNA expression pattern during follicular development in these two species, the results obtained allowed to conclude that cell proliferation varies according to follicular development and estrous cycle phase, both in bitches and queens, with both this variables having a significative interaction. In this context, the regulation of cell proliferation in the follicle may be a therapeutic route for fertility control (stimulation or contraception). However, this work will essentially serve as a basis for subsequent studies to better uncover the physiological processes that regulate folliculogenesis. In addition, the present work contributed to establish and optimize the immunohistochemical protocol in the FMV-ULHT research laboratory.
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Orientação: Daniel Murta
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MESTRADO INTEGRADO EM MEDICINA VETERINÁRIA, MEDICINA VETERINÁRIA, VETERINÁRIA, FELÍDEOS, CANÍDEOS, GATOS, CÃES, REPRODUÇÃO ANIMAL, ESTUDOS DE CASO, VETERINARY MEDICINE, FELIDS, CANIDS, CATS, DOGS, ANIMAL BREEDING, CASE STUDIES, FOLICULOGÉNESE, FOLLICULOGENESIS