An in vitro comparative study of follicle stimulating hormone (FSH) and activin A effects on the maturation of preantral follicle-enclosed oocytes from immature Syrian mice.

OBJECTIVES It was aimed to investigate the effects of different doses of follicle stimulating hormone (FSH) and activin A on the growth and maturation of preantral mouse follicles during the in vitro culture. METHODS Preantral follicles (90-100 microm in diameter) were harvested from 6-8 week-old Syrian mice and cultured in TCM199 culture medium for 6 days to see the effect of FSH and Activin A. Activin A concentrations in the range of 10-200 ng/ml were used, while 10, 50, 100, 150 and 200 mIU/ml FSH were used in the experiment. RESULTS Activin A concentration of 100 ng/ml resulted in a significant increase in follicle diameter (170 microm) with the survival rate of 73% as compared to the control (100 microm and 25%, P<0.05). The number of oocytes matured and the percentage of germinal vesicle breakdown (GVBD) was 61 and 70%, respectively as compared to the control (20 and 29%, P<0.05). Follicle diameter (190 microm) and survival rate (85%) increased significantly in the presence of 100 mIU/ml of FSH as compared to the control (P<0.05). But, the administration of activin A+FSH increased the effect of both factors on follicular diameter (205 microm as compared to 100 microm in control, P<0.01). Follicle survival, oocyte maturation and GVBD rates were 91, 81 and 89%, respectively (P<0.01). CONCLUSION These results have suggested that exposure to FSH and activin A before the formation of antral cavity had positive effect on follicle survival and oocyte robustness.