High doses of FSH induce autophagy in bovine ovarian granulosa cells via the AKT/mTOR pathway.

Abstract

Follicle-stimulating hormone (FSH) plays a critical role in follicular growth and granulosa cell function; however, the mechanism by which the aggressive stimulation of FSH leads to poorer oocyte quality and embryo development potential is unclear. In this study, bovine ovarian granulosa cells (BGCs) were challenged with FSH doses (vehicle, 0.1, 1, 10 and 100ng/ml) to investigate the effects of FSH on BGCs. The results indicated that the relative viability of BGCs was significantly increased in cells challenged with 1ng/ml FSH, whereas the viability was significantly decreased with 100ng/ml FSH treatment. The mRNA abundance of FSHR, CYP19, StAR and BAX was significantly upregulated with 1, 10 and 100ng/ml of FSH, while the BCL-2 mRNA level was downregulated with higher concentrations of FSH (10 and 100ng/ml). Furthermore, BGC autophagy was detected in cells treated with 10 and 100ng/ml FSH by MDC staining, and the mRNA abundance of LC3, BECN1, BNIP3, ATG3 and ATG7 was upregulated with increasing FSH concentration. Meanwhile, the protein expression of LC3 was increased in cells treated with 10 and 100ng/ml FSH. 1 and 10ng/ml FSH significantly increased E2 production, whereas 10 and 100ng/ml FSH significantly increased P4 production. FSH significantly inhibited the phosphorylation of AKT in cells treated with higher concentrations (1, 10 and 100ng/ml), while activating mTOR phosphorylation at concentrations of 10 and 100ng/ml of FSH. In summary, we can conclude that higher doses of FSH (10 and 100ng/ml) induce BGC autophagy via the AKT/mTOR signalling pathway.