Effects of α-lipoic acid on renal oxidative stress and apoptosis in diabetic rats

Objective To explore the role of oxidative stress on apoptosis in the kidneys of diabetic rats and the protecting effects of α-lipoic acid on the kidneys. Methods After the diabetic rat models were induced by intraperitoneal injection of streptozotocin (STZ), the diabetic rats were divided into two groups of non-treated (group DM, n=10) and α-lipoic acid -treated (group LA,n=10).The normal non-diabetic rats were served as the controls (group NC,n=10). The levels of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) in renal cortex were detected 12 weeks later. Apoptotic cells in the kidneys were identified by TUNEL, the expression of cystein asparate proteinase-3 (Caspase-3) was detected by immunohistochemistry. Results Compared with group NC, the levels of MDA were significantly elevated(P0.01),and the activity of SOD was significantly reduced in group DM(P0.01),and the number of apoptotic cells and the expression of Caspase-3 were significantly increased in group DM(P0.01). All markers above were improved by treatment with α-lipoic acid(P0.01).Conclusion Diabetes can cause high oxidative stress and excessive apoptosis.α-Lipoic acid has a protective effect on the kidneys by interfering the apoptosis through inhibiting oxidative stress and down-regulating the expression of Caspase-3.