Aralia taibaiensis Protects Cardiac Myocytes against High Glucose-Induced Oxidative Stress and Apoptosis

Patients with type 2 diabetes have increased cardiovascular disease risk compared with those without diabetes. Hyperglycemia can induce reactive oxygen species (ROS) generation, which contributes to the development of diabetic cardiomyopathy. Our previous study has demonstrated that the total saponins of Aralia taibaiensis (sAT), a frequently-used antidiabetic medicine in traditional Chinese medicine (TCM), can scavenge free radicals in vitro and have good anti-oxidant ability on lipid peroxidation of rat liver microsomes. This work was designed to investigate whether sAT could protect the heart while it was used in the treatment of diabetes. Oxidative stress was induced in H9c2 cells by high glucose (33 mM) and glucose oxidase (15 mU, G/GO) and the protective effects of sAT were evaluated. Treatment of H9c2 cells with G/GO resulted in an increase in cell death, intracellular ROS level and cell oxidative injury, which were markedly reduced by sAT treatment. Further study revealed that sAT induced the nuclear translocation of Nrf2 and expression of its downstream targets. Moreover, Nrf2 siRNA markedly abolished the cytoprotective effects of sAT. sAT exerted cytoprotective effects against oxidative stress induced by hyperglycemia and the cardioprotective effects of sAT might be through the Nrf2/ARE pathway. Thus, sAT might be a promising candidate for the treatment of diabetic cardiomyopathy.