Overexpression of microRNA-21-5p prevents the oxidative stress-induced apoptosis of RSC96 cells by suppressing autophagy

We aim to study the anti-apoptotic effect of microRNA-21-5p (miR-21-5p) in the oxidative stress-induced apoptosis of Schwann cells and the relevant mechanism in this research, laying a foundation for the treatment of peripheral neuropathy (PNP). The oxidative stress model was established by using hydrogen peroxide (H2O2). ROS level were detected by DCFH-DA (2,7-Dichlorodi-hydrofluorescein diacetate). Western blot and fluorescence staining were used to detect the apoptosis and autophagy level. The miR-21-5p overexpression model was established by transfection of miR-21-5p mimics into RSC96 cells. Five groups of control group, H2O2 group, H2O2 + chloroquine (CQ) group, H2O2 + miR-21-5p mimics group, and H2O2 + miR-21-5p mimics+rapamycin (RAPA) group were included in our experiment. Compared with control group, miR-21-5p was decreased in H2O2-treated RSC96 cells, while autophagy and apoptosis were both promoted. The result revealed that apoptosis was probably triggered by activation of autophagy in H2O2-treated group. In order to verify the relationship between autophagy and apoptosis more accurately, we used CQ to inhibit autophagy. Compared with H2O2-treated group, autophagy and apoptosis were both weakened in H2O2 + CQ group. Subsequently, we found the antiapoptotic effect of miR-21-5p in this model, overexpression of miR-21-5p prevented cells from being damaged by oxidative stress, it induced the decrease of PTEN and the level of autophagy, leading to decreased level of apoptosis. The identified relationship between miR-21-5p, apoptosis, and autophagy promotes us to find a new mechanism to improve the treatment for PNP.