EFFECT OF CADMIUM AND SELENIUM ON THE ANTIOXIDANT DEFENSE SYSTEM IN RAT KIDNEYS

To examine effects of exogenous Cd on the kidney antioxidant defense s ystem (AOS) and the possible protective role of Se against Cd toxicity , male Wistar albino rats (2 months old) were exposed during 30 days t o oral intake of 200 ppm Cd (as CdCl2), 0.1 ppm Se (as Na-selenite) or to the same dosages of Cd + Se, simultaneously. Marked accumulation o f Cd (23.44 +/- 0.69 mu g/g w.m.) and marked alterations of AOS, resul ting in kidney injury (renal pseudohypertrophy), were found in Cd-trea ted rats. Activities of total superoxide dismutase (SOD, EC 1.15.1.1), manganese-containing superoxide dismutase (MnSOD) and selenium-depend ent glutathione peroxidase (Se GSH-Px, EG 1.11.1.9) were significantly reduced, whereas that of glutathione-S-transferase (CST, EC 2.5.1.18) and vitamin E (vit E) concentration were significantly increased in t he kidneys of Cd-treated rats. Kidney catalase (CAT, EC 1.11.1.6) acti vity, ascorbic acid (AsA) and red blood cell glutathione one (GSH, GSS G) levels were not markedly influenced by Cd uptake. In kidneys of Se treated rats, the activities of total SOD, copper-zinc-containing supe roxide dismutase (CuZnSOD) and GST were significantly increased. Activ ities of kidney CAT and Se GSH-Px were largely unchanged, whereas sign ificant increases of the kidney AsA and vit E concentrations occurred. In Cd + Se-cotreated rats, the kidney activities of MnSOD, CAT and Se GSH-Px, as well as vit E concentration, were the same as in controls, whereas CuZnSOD and GST activities and concentration of AsA exceeded normal values. These data indicate that Se only partially improves the AOS that is insufficient to prevent Cd-induced nephrotoxicity. (C) 19 97 Elsevier Science Inc.