In brief: Genistein contributes to granulosa cell (GC) survival by two routes: one is that genistein induced p-AMPK and inhibited p-mTOR, which induces LC3 activation and autophagy; the other is that genistein inhibited caspase-3 and its cleavage, which induces PARP1 activation and PARylation.
Abstract: Genistein is an isoflavone which is beneficial for health, but little is known regarding its function on granulosa cell fate during follicular atresia. In the present study, we established an in vitro model of porcine follicular granulosa cell apoptosis by serum deprivation and showed that treatments with 1 μM and 10 μM genistein significantly reduced the apoptotic rate of granulosa cells compared to the blank control (P < 0.05). These results suggest that genistein at micromolar levels alleviates serum deprivation-induced granulosa cell apoptosis, and the ameliorative effect of genistein on granulosa cell apoptosis is likely to be able to inhibit nutrient depletion-induced follicular atresia. Further experimental results revealed that the expression of the autophagic marker protein LC3II in 100 nM-10 μM genistein treatment increased in a dose-dependent manner and was higher than the control (P < 0.05). Genistein also dose dependently promoted the phosphorylation of AMPK (adenosine 5'-monophosphate-activated protein kinase) in granulosa cells. Poly(ADP-ribose) (pADPr) formation in genistein-treated groups was also notably higher than in the controls (P < 0.05). Collectively, genistein alleviates serum deprivation-induced granulosa cells in vitro through enhancing autophagy, which involving AMPK activation and PARylation signaling. However, further study should be carried out to investigate the role of the aforementioned signaling on this process.