Morroniside protect human granulosa cells against H2O2-induced oxidative damage via regulating Nrf2 and MAPK signaling pathway

Abstract Background Morroniside is the main ingredient of Cornus officinalis, which has an antioxidant effect. Ovarian granulosa cells (GCs) are responsible for regulating the development and atresia of follicles, which are susceptible to oxidative stress. In this study, we investigated whether morroniside could inhibit oxidative stress of GCs induced by hydrogen peroxide (H2O2), thus leading to improve oocyte quality. Methods The study was divided into 5 groups: control group, H2O2 group, morroniside (5 µM) + H2O2, morroniside (10 µM) + H2O2, Morroniside (20 µM) + H2O2. Cell survival rate was determined by CCK-8, ROS fluorescence level was determined by DCFH-DA probe, MDA, 8-OHdG, T-AOC, SOD, NQO1 and caspase-3 were determined by ELISA, SOD, NQO1, Bax, Bcl-2, caspase-3, caspase-9, Nrf2 and MAPKs protein expression were determined by Western blot, and Nrf2 nuclear translocation level was determined by immunofluorescence method. SPSS21.0 was used for statistical data analysis. Results After pretreatment with morroniside, the levels of ROS, MDA and 8-OHdG in ovarian GCs were significantly decreased. Morroniside significantly upregulated the level of p-Nrf2 and promoted the nuclear translocation level of Nrf2, which transcriptionally activated antioxidase SOD and NQO1. In addition, the levels of apoptosis-related proteins Bax, Bcl-2, caspase-3 and caspase-9 were significantly regulated via p38 and JNK pathway by morroniside. Conclusions These results suggested that morroniside could reduce oxidative damage and apoptosis of ovarian GCs induced by H2O2 in multiple ways, which provided a new idea for clinical improvement of oxidative stress in female reproductive system.