Morroniside suppresses hydrogen peroxide-stimulated autophagy and apoptosis in rat ovarian granulosa cells through the PI3K/AKT/mTOR pathway

Abstract

Previous evidences have indicated that granulosa cells play a critical role in follicular growth. Hydrogen peroxide (H₂O₂)-induced oxidative stress has been associated with ovarian granulosa cell apoptosis and ovarian function. Recently, a study highlighted the protective role of morroniside against H₂O₂-induced damage. In this study, we aimed to investigate the effects of morroniside on H₂O₂-stimulated rat ovarian granulosa cells and its underlying molecular mechanisms. Our results showed that H₂O₂ treatment suppressed cell survival and increased apoptosis in rat granulosa cells, while treatment with morroniside markedly increased H₂O₂-induced granulosa cell survival in a dose-dependent manner (0, 10, 50 and 100 µM). Moreover, treatment with 50 µM morroniside impeded H₂O₂-induced cell apoptosis. An elevation in intracellular ROS, MDA, SOD, GSH-Px, and CAT level was observed in H₂O₂-induced granulosa cells; however, this effect was abrogated by morroniside treatment. Further studies suggested that administration of morroniside inhibited H₂O₂-induced granulosa cell apoptosis and caspase-3 activity. In addition, after morroniside treatment of H₂O₂-stimulated granulosa cells, autophagy-related protein (LC3-II/LC3-I ratio) and beclin-1 expression was decreased and p62 level was increased. Interestingly, we found that morroniside treatment activated the PI3K/AKT/mTOR pathway in H₂O₂-stimulated granulosa cells. Finally, we showed that treatment with PI3K and mTOR inhibitors reversed the protective effects of morroniside on H₂O₂-induced granulosa cells. Taken together, our data suggest that treatment with morroniside decreased apoptosis, autophagy, and oxidative stress in rat granulosa cells through the PI3K/AKT/mTOR pathway.