Effect of chronic cadmium exposure on antioxidant defense system in some tissues of rats: Protective effect of selenium

The effects of selenium ( Se) on antioxidant defense system in liver and kidneys of rats with cadmium (Cd)-induced toxicity were examined. Cd exposure (15 mg Cd/kg b.m./day as CdCl2 for 4 weeks) resulted in increased lipid peroxidation ( LP) in both organs (p < 0.005 and p < 0.01). Vitamin C (Vit C) was decreased in the liver ( p < 0.005), whereas vitamin E ( Vit E) was increased in the liver and kidneys ( p < 0.005 and p < 0.05) of Cd-exposed animals. Superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were decreased in both tissues ( p < 0.05 and p < 0.005), whereas catalase (CAT) activity was decreased only in liver ( p < 0.005). Glutathione S-transferase (GST) increased in both tissues ( p < 0.005 and p<0.01). Treatment with Se (0.5 mg Se/kg b.m./day as Na2SeO3 for 4 weeks) significantly increased liver and kidneys SOD and GSH-Px activities ( p < 0.05 to p < 0.005), as well as CAT and GST activities only in the liver ( p < 0.01). In animals exposed to Se, both the concentrations of Vit C ( p < 0.01) and Vit E (p < 0.005) were increased in both tissues. Co-treatment with Se resulted in reversal of oxidative stress with significant decline in analyzed tissues Cd burden. Our results show that Se may ameliorate Cd-induced oxidative stress by decreasing LP and altering antioxidant defense system in rat liver and kidneys and that Se demonstrates the protective effect from cadmium-induced oxidative damage.nul