Ginsenoside Rb3 provides protective effects against cisplatin-induced nephrotoxicity via regulation of AMPK-/mTOR-mediated autophagy and inhibition of apoptosis in vitro and in vivo

Objectives: Based on previous reports that ginsenosides have been shown to exert better preventive effects on cisplatin-induced kidney injury, the present work aims to evaluate the protective effects of ginsenoside Rb3 (G-Rb3) on cisplatin-induced renal damage and underlying mechanisms in vivo and in vitro.

Materials and methods: The protective effect of G-Rb3 on cisplatin-induced acute renal failure in ICR mouse model and HEK293 cell model was investigated, and the underlying possible mechanisms were also explored. For animal experiment, renal function, kidney histology, inflammation, oxidative stress, relative protein molecules involved in Apoptosis and Autophagy signalling pathways were assessed. In addition, rapamycin (a specific inhibitor of mTOR), compound C (a specific inhibitor of AMPK) and acetylcysteine (NAC, a specific ROS scavenger) were employed to testify the effects of AMPK/mTOR signal pathway on the protective effects of G-Rb3 in HEK293 cells.

Results: Pre-treatment with G-Rb3 at doses of 10 and 20 mg/kg for ten days significantly reversed the increases in serum creatinine (CRE), blood urea nitrogen (BUN) and malondialdehyde (MDA), and decrease in glutathione (GSH) content and superoxide dismutase (SOD) activity. Histopathological examination further revealed that G-Rb3 inhibited cisplatin-induced nephrotoxicity. G-Rb3 diminished cisplatin-induced increase in protein expression levels of p62, Atg3, Atg5 and Atg7, and decrease in protein expression level of p-mTOR and the ratio of LC3-I/LC3-II, indicating that G-Rb3 suppressed cisplatin-induced activation of Autophagy. Inhibition of Autophagy induced inactivation of Apoptosis, which suggested that Autophagy played an adverse effect on cisplatin-evoked renal damage. Further, we found that G-Rb3 might potentially modulate the expressions of AMPK-related signal pathways.

Conclusions: These findings clearly suggested that G-Rb3-mediated alleviation of cisplatin-induced nephrotoxicity was in part due to regulation of AMPK-/mTOR-mediated Autophagy and inhibition of Apoptosis in vitro and in vivo.