Protection of doxorubicin-induced DNA damage by sodium selenite and selenomethionine in Wistar rats

The importance of selenium in human nutrition is well recognized. It is an important micronutrient involved in antioxidant defense and is of fundamental importance in the maintenance of genomic stability. However, questions relating to the appropriate chemical form of selenium used for supplementation and its beneficial dose is still being debated. Therefore, the present study investigated the ability of 2 selenium compounds-sodium selenite (SS) and selenomethionine (SM)-to protect DNA against the damage induced by doxorubicin (DXR). Wistar rats were supplemented orally for 10 consecutive days with SS or SM (I and 2 mg/kg bw); 24 hours before euthanasia a single dose of DXR (90 mg/kg bw) was injected intraperitoneally. DNA lesions were assessed by the comet assay and micronucleus test; the concentrations of thiobarbituric acid reactive substances, vitamin E, and reduced glutathione were determined by using liver homogenates. The results obtained showed that SS and SM prevented the induction of DNA damage by DXR. It was also observed that these 2 selenium compounds increased the hepatic concentration of glutathione, maintained the thiobarbituric acid reactive substances, and allowed for the maintenance of hepatic concentrations of vitamin E even after DXR treatment, confirming the antioxidant properties of selenium compounds. Sodium selenite and SM supplementation exhibited very similar patterns of protection. In conclusion, SS and SM supplementation was effective in protecting DNA against DXR-induced DNA damage in Wistar rats, probably because of their antioxidant properties. (C) 2007 Elsevier Inc. All rights reserved.