In the present study, the effects of alpha lipoic acid (ALA) supplementation on glycemic control, lipid profile, vitamin C, lipid peroxidation and antioxidant enzymes in streptozotocin (STZ)-induced diabetic rats have been evaluated. This study was carried out on 80 male rats. The rats were divided into four equal groups of 20 rats each. Group Ι :( Control group): Injected with citrate buffer only. Group Π :( Diabetic group): Injected with a single intraperetinoel (i.p) dose of 50 mg/kg of streptozotocin for diabetes induction. Group III :( diabetic alpha lipoic acid treated group) and Group IV :( control alpha lipoic acid treated group). ALA was injected intrperetinoel in a daily dose of 54 mg/kg bw. Blood samples for serum separation and liver and kidney tissues were collected from all animal groups two times at 4 and 6 weeks from the onset of treatment with α-lipoic acid which begin after five weeks of diabetes induction. All sera were processed directly for determination of glucose, total cholesterol, triacylglycerols, HDL–C, LDL-C, VLDL-C and vitamin C in addition to liver and kidney L- malondialdehyde (L- MDA) and antioxidant enzymes were also determined. The obtained results revealed that, a significant increase in serum glucose, total cholesterol, triacylglycerols, LDL-C, VLDL-C, HDL-C, vitamin C and L-MDA concentrations in liver and kidney as well as marked reduction in CAT, SOD and GpX activites of liver and kidney were observed in STZ-induced diabetic rats.
Treatment with ALA to STZ-induced diabetic rats lowered serum glucose, total cholesterol, triacylglycerols, LDL-C, HDL-C concentration and lipid peroxidation of liver and kidney as well as significantly increased serum vitamin C and liver catalase activity. These results suggest that, ALA may be effective in controlling glycemic status and improving dyslipidemia and has the potential in reducing cardiovascular complications due to diabetes mellitus. In addition, treatment with ALA improved significantly the diabetes-induced deterioration of vitamin C and attenuates the status of antioxidant enzymes and biomarkers of oxidative stress produced by diabetes mellitus.