Determine the Role of FSH Receptor Binding Inhibitor in Regulating Ovarian Follicles Development and Expression of FSHR and ERα in Mice

Mice of FRBI-1, FRBI-2, and FRBI-3 groups were intramuscularly injected with 20, 30, and 40mg/kg, respectively, for five consecutive days. Ovarian weights of three FRBI groups were reduced in comparison with FSH group. Ovarian cortex thicknesses (OCT) of the FRBI-3 group were less than that of the FSH group (P<0.05). As compared to FSH group, there were fewer numbers of secondary follicles (SFs) and mature follicles (MF) on the ovaries of FRBI-treated mice numbers of primary follicles (PFs) and SFs also decreased. In FRBI-3 mice, we found that the primordial follicles (POF) were scarcer, the follicles developed poorly, and granulosa cells became apoptosis. SF numbers of FRBI-2 and FRBI-3 groups were less than that of the FSH group on day 20 (P<0.05). Maximum longitudinal diameter (MLD) and transverse diameter (MTD) of three FRBI groups became decreased during the experiment. MLD and MTD of the FRBI-3 group were smaller than FSH group. Levels of FSHR mRNA and protein were less than that of CG and FSH group (P<0.05). ERα protein levels of FRBI group and serum concentrations of FSH and estradiol (E(2)) in the FRBI-treated mice were decreased when compared to CG and FSH group. In conclusion, FSH treatment could increase the numbers of SF and MF, enhance follicle development, reduce the numbers of SF and MF, and depress the follicular development of mice. Furthermore, FRBI declined the mRNA and protein levels of ERα and FSHR in the ovaries and dropped serum concentrations of FSH and E(2) of mice.