Protective Effect of Gynura Bicolor Alcohol Extracts on Rat Kidney Epithelial NRK-52E Cells Induced by Tert-Butyl Hydroperoxide

Abstract

Background: Gynura bicolor is a common vegetable in the Asia and has many physiological effects. We aimed to investigate the renoprotective effects of G. bicolor alcohol extracts (GBAEs). Methods: Rat kidney epithelial NRK-52E cell culture and kidney damage induction by tert-butyl hydroperoxide (t-BHP) were used as experimental models. In this study, the antioxidative and anti-inflammatory activities, the levels of apoptosis and apoptosis-related molecules were analyzed in NRK-52E cells following t-BHP-induced injury. Results: The results showed the levels of thiobarbituric acid reactive substances (TBARS) and reactive oxygen species (ROS) decreased by levels by 61-71% and 41-59%, respectively, in NRK-52E cells treated with 0.5, 1, or 5 mg/ml GBAE combined with t-BHP compared with t-BHP-induced cells (p<0.05). The GSH levels and GSH-to-GSSG ratio were increased in NRK-52E cells treated with 0.5, 1, and 5 mg/ml GBAE combined with t-BHP compared to t-BHT-induced cells (p<0.05). The nitrite (NO), prostaglandin E2 (PGE2), IL-6, and TNF-α levels of NRK-52E cells treated with 0.5, 1, and 5 mg/ml GBAE combined with t-BHP were decreased compared with t-BHP-induced cells (p<0.05). In addition, Bcl-2 levels were increased after treatment with 5 mg/ml GBAE combined with t-BHP, and the levels of Bax and poly (ADP-ribose) polymerase (PARP) and the apoptosis percentage were decreased after treatment with 1 or 5 mg/ml GBAE combined with t-BHP induction compared to after t-BHP induction alone (p<0.05). Conclusions: These data showed that 5 mg/ml GBAE can protect against kidney cell damage induced by t-BHP. The mechanism involves reducing cell damage and apoptosis through decreasing oxidative stress and inflammation.