Effect of alpha-lipoic acid supplementation on blood pressure, renal oxidant-antioxidant status and renal damage in spontaneously hypertensive rats

Objective:To investigate the effect of alpha-lipoic acid(ALA)supplementation on systolic blood pressure(SBP),renal oxidant-antioxidant status and renal damage in spontaneously hypertensive rats(SHR)and SHR administered with Nω-nitro-L-arginine methyl ester(L-NAME).Methods:Male rats were divided into four groups(SHR,SHR+ALA,SHR+L-NAME,SHR+ALA+L-NAME).The respective group of rats was administered with ALA(100 mg/kg/day)from age 4 weeks to 28 weeks and L-NAME(25 mg/kg/day)from age 16 weeks to 28 weeks.SBP was measured every two weeks and twenty four hour urine was collected at 4 weeks,16 weeks and 28 weeks for estimation of protein,creatinine and N-acetyl-e end of 28 weeks,rats were sacrificed and blood and kidneys colα-Dglucosaminidase.At thlected for assessment of blood creatinine,kidney thiobarbituric acid reactive substances,protein carbonyls,superoxide dismutase,catalase,glutathione peroxidase,glutathione reductase,glutathione S-transferase,glutathione disulfide,glutathione,total antioxidant status and nitric oxide as well as histopathological examination.Results:ALA supplementation significantly reduced SBP of SHR and SHR+L-NAME rats when compared to their respective non-supplemented groups.Renal oxidant status markers including thiobarbituric acid reactive substances and protein carbonyls were significantly reduced on SHR and SHR+L-NAME rats supplemented with ALA at 28 weeks as well as ALA supplementation significantly increased renal antioxidants including superoxide dismutase,catalase,glutathione peroxidase,glutathione S-transferase,glutathione and glutathione/glutathione disulfide ratio at 28 weeks.No significant change in nitric oxide levels was observed between the ALA supplemented and non-supplemented groups.Renal dysfunction was ameliorated on ALA supplementation as evidenced by significant reduction in urine protein levels,N-acetyl-α-D-glucosaminidase activity and significant increase of creatinine clearance in SHR and SHR+L-NAME at 28 weeks.Renal histopathological examination showed that ALA supplementation prevented vascular damage in SHR and ameliorated glomerular damage in SHR+L-NAME at 28 weeks.Conclusions:ALA has hypotensive and renoprotective effects on both SHR and SHR+LNAME,which could be due to its ability to ameliorate oxidative stress in the kidneys.