Total cornus officinalis glycosides inhibit high glucose-induced cell apoptosis and oxidative damage of human renal tubular epithelial cell line HK-2

Objective To investigate the effect of cornus officinalis glycosides on apoptosis and oxidative damage of human renal tubular epithelial cells line induced by high glucose by regulating E2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway. Methods Human renal tubule epithelial cell line HK-2 was divided into control group (control, 5.5 mmol/L glucose), model group (HG, 30 mmol/L glucose), and total cornus officinalis glycosides groups with low, medium and high dose (L-COG, M-COG, H-COG). After Nrf2 pathway inhibitors were added, HK-2 cells were divided into H-COG group and ML385 group. CCK8 method was used to detect cell activity. Apoptosis was detected by flow cytometry. The expressions of Bcl-2 associated X protein (Bax), B-cell lymphoma/leukemia 2 (Bcl-2), activated caspase3 (cleaved caspase3), Nrf2/HO-1 pathway protein were detected by Western blot. Reactive oxygen species (ROS) content was detected by DCFH-DA, glutathione peroxidase (GSH-Px) activity, superoxide dismutase (SOD) activity, interleukin-6 (IL-6) content and tumor necrosis factor α (TNF-α) content were detected by ELISA. Results Compared with control group, the cell activity, Bcl-2 protein expression, GSH-Px and SOD activity in model group were significantly decreased, and the apoptosis rate, Bax, Nrf2, HO-1 and cleaved caspase3 protein expression, ROS, IL-6 and TNF-α content were significantly increased (P＜0.05). Compared with model group, the cell activity, Bcl-2 protein expression, GSH-Px and SOD activity of L-COG, M-COG, and H-COG were significantly increased. Apoptosis rate, Bax, Nrf2, HO-1, cleave-caspase3 protein expression, ROS, IL-6, TNF-α content were significantly decreased (P＜0.05). Compared with H-COG, the cell activity, Bcl-2 protein expression, GSH-Px and SOD activity in ML385 group were significantly increased. The apoptosis rate, Bax and cleaved caspase3 protein expression, ROS, IL-6, TNF-α content were significantly decreased (P＜0.05). Conclusions The total cornus officinis glucoside may reduce the oxidative stress and inflammatory response of renal tubular epithelial cells induced by high glucose through inhibiting Nrf2/HO-1 pathway and then reduce cell apoptosis.