ABSTRACT
The aim of the present study was to determine the role of GDF-9 and/or FSH on the growth and mRNA expression for FSH-R, GDF-9, and BMPs in goat secondary follicles after culture in vitro. Goat secondary follicles (~200µm) were isolated and cultured for six days in minimum essential medium (MEM) supplemented with GDF-9 (200 ng/mL), FSH (50 ng/mL) or both. At the beginning and end of culture, the follicular diameter was evaluated and compared. The levels of mRNA for GDF-9, FSH-R and BMPs -2, -4, -6, -7 and -15 in cultured follicles were quantified by real time PCR. The results showed that a significant increase of follicle diameter after six days when compared to day 0, but the presence of GDF-9 and FSH did not influence the follicular growth in comparison with those cultured in MEM. Real time PCR showed that GDF-9 down-regulated the levels of mRNA for BMPs -2 and -15, while FSH either alone or in combination with GDF-9 did not affect the expression of GDF-9, FSH-R and BMPs. In conclusion, GDF-9 reduced the expression of BMP-2 and -15 in caprine preantral follicles after their culture, but FSH either alone or in association with GDF-9 did not control the expression of GDF-9, FSH-R and BMPs.
ABSTRACT
This study investigated the levels of messenger ribonucleic acids (mRNA) for inhibin-ßA subunit in goat primordial, primary and secondary follicles, as well as in cumulus-oocyte complexes (COCs) and mural granulosa / theca cells of antral follicles. The effects of activin-A (100ng mL-1) and/or follicle stimulating hormone (FSH, 50ng mL-1) on growth and expression of mRNA for activin-A and FSH receptor (FSH-R) in secondary follicles cultured for six days were evaluated. The data showed that the expression of inhibin-ßA is lower in secondary follicles than in primary follicles and is higher in large antral follicles than in small antral follicles. After culture, activin-A and/or FSH promoted growth of secondary follicles, while FSH increased the levels of mRNA for inhibin-ßA, and activin-A increased the levels of FSH-R mRNA. In conclusion, mRNA for inhibin-ßA is expressed at different levels in pre-antral and antral follicles and activin-A acts as a stimulator of the FSH-R expression in goat follicles. On its turn, the expression of inhibin-ßA is stimulated by FSH, which together with activin-A promotes secondary follicle growth in-vitro.
Este estudo investigou os níveis de ácidos ribonucleicos (RNAm) para a subunidade ßA da inibina em folículos primordiais, primários e secundários caprinos, bem como em complexos cumulus-oócitos (CCOs) e células da granulosa mural/teca de folículos antrais. Além disso, avaliaram-se os efeitos da ativina-A (100ng mL-1) e/ou hormônio folículo estimulante (FSH, 50ng mL-1) sobre o crescimento e a expressão do RNAm para inibina-ßA e receptores de FSH (FSH-R) em folículos secundários cultivados por seis dias. Os dados mostraram que a expressão de inibina-ßA é menor em folículos secundários do que em folículos primários e é maior em grandes folículos antrais que nos pequenos folículos antrais. Após o cultivo, ativina-A e/ou FSH promoveram o crescimento de folículos secundários. Enquanto o FSH aumentou os níveis de RNAm para inibina-ßA, a ativina-A aumentou os níveis de RNAm para FSH-R. Em conclusão, a inibina-ßA é expressa em diferentes níveis em folículos pré-antrais e antrais e a ativina-A atua como um estimulador da expressão de FSH-R em folículos caprinos. Por sua vez, a expressão de inibina-ßA é estimulada pelo FSH, que, juntamente com ativina, promove o crescimento de folículos secundários in vitro.