Comparative study on the effect of antioxidants α-lipoic acid and N-acetyl cysteine on the structure of the renal tubules of diabetic rabbits

Background and objectives Hyperglycemia-induced oxidative stress plays a central role in the pathogenesis of diabetic complications. The therapeutic potential of antioxidants in the prevention and treatment of these complications is an emerging research area. The roles of α-lipoic acid (ALA) and N-acetyl cysteine (NAC) in the protection against oxidative stress in alloxan-induced diabetic rabbits were assessed both biochemically and histologically in this study. Materials and methods Thirty-two mature male rabbits were used in this study. They were divided into two groups: the control group (n=8) and the experimental (n=24) group; the experimental group was injected intraperitoneally with alloxan (180mg/ml/kg body weight). After 3 weeks, this group (diabetic rabbits) was subdivided into three subgroups of eight rabbits each. The first one was left as the untreated diabetic subgroup; rabbits in the second and third subgroups were treated daily for 7 days with ALA and NAC (100 mg/ml/kg body weight), respectively. At the end of the experiment, blood and kidney sections were processed for biochemical and histological studies. Results The renal tubules showed degenerative and apoptotic changes, which were associated with increased DNA fragmentation and lipid peroxidation in the kidney tissues, as well as reduction in the capacity of the antioxidant defense system. However, treatment of diabetic rabbits with either ALA or NAC ameliorated diabetesinduced oxidative stress. Conclusion ALA and NAC could be useful in the prevention and treatment of oxidative stress associated with hyperglycemia. This action seems to result mainly from direct scavenging of reactive oxygen species and restoring of the GSH (glutathione) redox state.