Effects of BMP-7 and FSH on the development of goat preantral follicles and levels of mRNA for FSH-R, BMP-7 and BMP receptors after in-vitro culture

Abstract

This study aimed to evaluate the effects of FSH and BMP-7 on growth and on expression of FSH-R, BMP-7 and BMP receptors in cultured secondary follicles. Goat secondary follicles (~200 µm) were isolated and cultured in vitro, with 5% CO2 in air at 39°C, for 6 days in the presence of BMP-7 (50 ng/ml) supplemented or not with FSH (50 ng/ml). Follicular diameter and the formation of the antrum were evaluated before and after culture. For each treatment, at the end of culture period, groups of 6 follicles were collected and, after extraction of total RNA and cDNA synthesis, the levels of mRNA for FSH-R, BMP-7 and BMP receptors in cultured secondary follicles were quantified by real time PCR. The results showed that addition of BMP-7 or FSH to culture medium stimulated growth of secondary follicles, while addition of both BMP-7 and FSH was needed to significantly increase the percentage of follicles forming an antrum and the follicular levels of mRNA for both BMP-7 and FSH-R. For BMP receptors, FSH reduced the levels of mRNA for BMPR-IA and BMP-RII in comparison with those follicles cultured in MEM alone and supplemented with BMP-7, respectively. In conclusion, like FSH, BMP-7 affects in vitro growth of cultured secondary follicles, but it stimulates antrum formation and expression of the mRNA's for BMP-7 and FSH-R only in presence of both BMP-7 and FSH. However, the levels of mRNA for BMP-RIA and BMP-RII are reduced in follicles cultured in medium supplemented with FSH.