Effects of high-fat mixed-lipid diet and exercise on the antioxidant system in skeletal and cardiac muscles of rats with colon carcinoma

Epidemiological and experimental studies suggest that eating habits and a sedentary lifestyle play a critical role in the incidence of colon carcinoma. In order to investigate the effects of high-fat mixed-lipid (HFML) diet in conjunction with long-term swimming, the antioxidant capacity of skeletal and cardiac muscles were observed in rats with 1,2-dimethylhydrazine (DMH)-induced colon carcinoma. Male Wistar rats were randomly divided into one control group and four cancer groups: sedentary and swimming groups fed low fat corn oil diet and sedentary and swimming groups, fed a HFML diet. After 6 months of swimming, rats were sacrificed and the blood, cardiac and soleus muscle were taken for analysis. Serum cholesterol, triglyceride and glucose concentrations were measured and the activity of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase as well as levels of malondialdehyde and glutathione were determined.The results showed that endurance swimming prevented lipid peroxidation in the soleus muscle of HFML diet rats due to elevated activities of antioxidant enzymes. On the other hand, increased lipid peroxidation in the hearts of all cancer groups indicated that DMH-induced colon carcinoma impaired the antioxidant status of the heart. This failure in heart tissue indicated that enhanced antioxidant capacity after regular physical activity is not sufficient to offset oxidative stress caused by DMH-induced colon carcinoma.