Résumé
We have investigated the protective effect of vitamin C and E together supplementation on oxidative stress and antioxidant enzyme activities in the liver of streptozotocin-induced diabetic rats, unsupplemented diabetic and control rats. We also determined the levels of both the vitamins and oxidative stress in plasma. Vitamin supplementation in diabetic rats lowered plasma and liver lipid peroxidation, normalised plasma vitamin C levels and raised vitamin E above normal levels. In liver, the activity of glutathione peroxidase was raised significantly and that of glutathione-S-transferase was normalised by vitamin supplementation in diabetic rats. The levels of lipid peroxidation products in plasma and liver of vitamin-supplemented diabetic rats and activities of antioxidant enzymes in liver suggest that these vitamins reduce lipid peroxidation by quenching free radicals.
Sujets)
Animaux , Antioxydants/métabolisme , Acide ascorbique/pharmacologie , Diabète expérimental/traitement médicamenteux , Femelle , Peroxydation lipidique/effets des médicaments et des substances chimiques , Foie/effets des médicaments et des substances chimiques , Rats , Rat Sprague-Dawley , Vitamine E/pharmacologieRésumé
Alloxan diabetic rats supplemented with vitamin C (ascorbic acid) orally in drinking water had increased plasma and liver ascorbic acid as compared to unsupplemented diabetic rats. The levels of liver reduced glutathione also increased in vitamin C supplemented diabetic rats as compared to non-supplemented diabetic rats. Vitamin C supplementation did not have any effect in reducing increased liver lipid peroxidation in diabetic rats. The results of the present study suggest that diabetes results in decreased levels of protective antioxidant species and vitamin C is effective to some extent in maintaining levels of plasma and liver ascorbic acid and liver reduced glutathione.
Sujets)
Animaux , Acide ascorbique/usage thérapeutique , Diabète expérimental/traitement médicamenteux , Compléments alimentaires , Femelle , Stress oxydatif , Rats , Rat Sprague-DawleyRésumé
Free radicals may play an important role in causation and complications of diabetes mellitus. Antioxidant status of blood was determined in rats made diabetic in intraperitoneal injection of streptozotocin (75 mg/kg body weight). The product of lipid peroxidation malondialdehyde in erythrocytes (RBC) was increased in diabetic rats as compared to normal controls after 6 weeks of induction of diabetes. The levels of major natural protective antioxidants, viz. glutathione and alphatocopherol (vitamin E) were lower in RBC and plasma respectively of diabetic rats as compared to normal controls. The results indicate that increased oxidative stress and accompanying decrease in antioxidants may be related to the causation of diabetes mellitus.