Evaluation of X-ray induced oxidative stress in cardiac tissue of albino wistar rats

Radiotherapy is increasingly used in the treatment of cancer, even though injurious effects of radiations is due to the production of free radicals. The study of normal tissue response and tissue injury after exposure to low and moderate dose is of great importance to cancer patients subjected to radiotherapy. Hence, this study attempts to explore the mechanism of oxidative stress in the myocardium of rats exposed to various doses of X rays. Albino rats were administered whole body radiation of 4Gy (groupII), 6 Gy(groupIII) and 6.6 Gy(groupIV) per minute and were divided into three groups of 6 animals each. Rats that were not irradiated served as control group(group I). Glutathione, Superoxide dismutase, catalase were estimated in rat myocardium homogenate by spectrophotometric method, to assess the antioxidant status and lipid peroxidation measurement indicated free radical toxicity. Cardiac tissue MDA increased significantly in rats exposed to 4,6,6.6 Gy of X rays compared to controls. The percentage increase in lipid peroxidation was proportional to the intensity of radiation. Tissue GSH, SOD and catalase activities declined significantly in all the X ray irradiated rats compared to controls. Intergroup comparison showed significant increase in MDA levels and statistically significant decrease in antioxidants between Group II vs Group III vs Group IV. To summarise, there is a significant increase in oxidative stress as indicated by increased lipid peroxidation and decrease in antioxidants in cardiac tissue of rats exposed to X rays. These findings establish a link between oxidative stress and X ray irradiation.