Restorative effects of zinc and selenium on cadmium-induced kidney oxidative damage in rats

To investigate whether cadmium-induced oxidative stress in the kidney is influenced by zinc and selenium.

Five groups of rats were maintained: (A) Cd (CdCl2, 400 micrograms.kg-1.day-1 intraperitoneal injection); (B) Cd + Zn (ZnCl2, 20 mg.kg-1.day-1 hypodermic injection); (C) Cd + Se (Na2SeO3, 350 micrograms.kg-1.day-1 via a stomach tube); (D) Cd + Zn + Se; (E) treated with physiological saline as a sham-handled control. The rats were given treatment for a period of 4 weeks. The activities of superoxide dismutase (SOD), glutathione peroxidase (GH-Px), catalase (CAT), and the level of malondialdehyde (MDA) in the kidney tissue were measured to assess the oxidative stress. Urinary lactate dehydrogenase (LDH) activity was used as an indicator of tubular cell damage caused by lipid peroxidation.

In group C and D, activities of SOD (110.5 +/- 5.2, 126.8 +/- 7.0; P < 0.05) and GSH-Px (85.7 +/- 4.9, 94.6 +/- 7.3; P < 0.05) were higher than those in group A (84.7 +/- 3.3; 56.9 +/- 3.8); and in group B, only the activity of GSH-Px (80.0 +/- 4.3, P < 0.01) increased in comparison with that in group A (56.9 +/- 3.8). Significant increase of MDA (P < 0.05) was seen in group B (31.1 +/- 4.7) and C (35.0 +/- 4.1) when compared with control values (17.2 +/- 1.8). No difference was found in the level of MDA between group D (18.9 +/- 2.6) and control. The activity of LDH in urine of control group (0.06 +/- 0.02) was lower than that of group A (0.46 +/- 0.19, P < 0.05), B (0.10 +/- 0.05, P < 0.05) and C (0.14 +/- 0.07, P < 0.05), and there was no significant change between control (0.06 +/- 0.02) and group D (0.08 +/- 0.02).

Zinc or selenium could partially alleviate the oxidative stress induced by cadmium in kidney, but administration cadmium in combination with zinc and selenium efficiently protects kidney from cadmium-induced oxidative damage.