IMPAIRED ANTIOXIDANT DEFENSE SYSTEM IN THE KIDNEY TISSUES FROM RABBITS TREATED WITH CYCLOSPORINE - PROTECTIVE EFFECTS OF VITAMIN-E AND VITAMIN-C

Enzymatic antioxidant defense system and antioxidant defense potential (AOP) were studied in kidney tissue from rabbits treated with cyclosp orine (CsA, 25 mg/kg/day), antioxidant vitamins (E, 100 mg/kg/day plus C, 200 mg/kg/day), and CsA plus antioxidant vitamins, and in kidney t issue from control animals. Although no change was observed in superox ide dismutase (SOD) activity, glutathione peroxidase (GSH-Px) and cata lase (CAT) activities were found decreased in kidney tissue exposed to CsA for 10 days compared with control tissue. The level of thiobarbit uric acid-reagent substances (TBARS) was higher and antioxidant defens e potential (AOP) lower in the CsA-treated group compared with the oth er groups. Histopathological examination reveals important subcellular damage in the renal tissue from the animals treated with CsA. Antioxi dant vitamin therapy caused full improvement in the enzyme activities, TBARS levels and AOP, but the subcellular damage was partly ameliorat ed in the CsA plus vitamin group. Results suggest that CsA impairs the antioxidant defense system and reduces the antioxidant defense potent ial in the renal tissue. Antioxidant vitamin treatment protects the ti ssue in part against toxic effects of the drug.