Protective effect of ginsenoside Rk1, a major rare saponin from black ginseng, on cisplatin-induced nephrotoxicity in HEK-293 cells.

Cisplatin, as one of the most effective chemotherapeutic agents, its clinical use is limited by serious side effect of nephrotoxicity. Cisplatin-induced nephrotoxicity is closely related to apoptosis induction and activation of caspase. The present study aimed to explore the potential protective effect of ginsenoside Rk1 (Rk1), a rare ginsenoside generated during steaming ginseng, on cisplatin-induced nephrotoxicity and the underlying mechanisms in human embryonic kidney 293 (HEK-293) cells. Our results showed that the reduced cell viability induced by cisplatin could significantly recover by Rk1. Furthermore, glutathione (GSH) as an oxidative index, was elevated and the lipid peroxidation product malondialdehyde (MDA) was significantly decreased after Rk1 treatment compared to the cisplatin group. Additionally, Rk1 can also decrease the ROS fluorescence expression and increase the protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) compared to the cisplatin group, which suggested a suppression of oxidative response. More importantly, the cisplatin-induced elevated protein levels of Bax, cleaved caspase-3, cleaved caspase-9, and decreased protein level of Bcl-2 were reversed after treatment with Rk1. Our results elucidated the possible protective mechanism of Rk1 for the first time, which may involve in its anti-oxidation and anti-apoptosis effects.