ALA/LA ameliorates glucose toxicity on HK-2 cells by attenuating oxidative stress and apoptosis through the ROS/p38/TGF-β(1) pathway

BACKGROUND: Growing evidence indicates that oxidative stress (OS) plays a pivotal role in Diabetic nephropathy (DN). In a previous study we demonstrated that ALA/LA protected HK-2 cells against high glucose-induced cytotoxicity. So we aimed to establish the glucose injury model of HK-2 cells and investigate the beneficial effects of ALA/LA on high glucose-induced excessive production of TGF-β1 and the possible mechanisms mediating the effects. METHODS: The expression of OS markers in high glucose-induced HK-2 cells treated with ALA/LA., including the antioxidant enzymes and reactive oxygen species (ROS) production, as well as the apoptosis rate were assayed by ELISA and flow cytometry. The p38/transforming growth factor β(1) (TGF-β(1)) signal pathway were measured by real-time RT-PCR and western blot. RESULTS: The modeling condition of glucose toxicity on HK-2 cells was at the glucose concentration of 40.9 mM. ALA/LA can significantly increase the activities of antioxidant enzymes and decrease ROS production stimulated by high glucose. The study also found that ALA/LA caused a decrease in the apoptosis rate and TGF-β(1) level of HK-2 cells under high glucose stress through the ROS/p38 pathway. CONCLUSIONS: ALA/LA exerts protective effects in vitro through inhibition of ROS generation, down regulation of the activation of the p38MAPK pathway and the expression of TGF-β(1) in HK-2 cells.