Effects of Alpha-Lipoic Acid on Oxidative Stress Induced Pancreatic Islet Cell Apoptosis in Type 2 Diabetic Rats

[Objective] To assess the effects of alpha-lipoic acid on oxidative stress induced pancreatic islet cell apoptosis in type 2 diabetic rats. [Methods] High-calorie diet combined with intraperitoneal injection of low-dose streptozotocin was used to establish a type 2 diabetic rat model. Then the model rats were treated by alpha-lipoic acid(15, 30, 60, and 120 mg/kg body weight) for 12 weeks before detecting pancreatic oxidative stress, apoptosis of pancreatic cells, and changes in the expression levels of pancreatic apoptosis-related proteins. [Results] The pancreatic malondialdehyde levels were significantly decreased in all alpha-lipoic acid intervented groups(P 0.01), while the total superoxide disumutase and the glutathione peroxidase activities were significantly increased(P 0.01), compared with the model control rats. The apoptotic indices were significantly decreased(P 0.01) in all intervention groups except the 15 mg/kg body weight group, compared with the model control rats, and the highest intervention effect was found in the 60 mg/kg body weight group. The protein levels of Bax, Fas, activated Caspase-9 and Caspase-3 decreased, and the Bcl-2 protein level increased significantly in all intervention groups. [Conclusion] Apoptosis rates of pancreatic cells are down-regulated by alpha-lipoic acid via ameliorating pancreatic oxidative stress and related protein levels.