The antioxidant response of the liver of male Swiss mice raised on a AIN 93 or commercial diet

Malondialdehyde (MDA) and hydrogen peroxide (H2O2) concentrations and superoxide dismutase (SOD) and glutathione reductase (GR) activities determined in the liver were lower in the group of mice fed with the AIN 93 diet, while catalase (CAT) activity was higher in the same group, when compared to the group fed on the commercial diet. Liver glutathione peroxidase (GSH-Px) activity was similar in the groups fed on either AIN 93 or the commercial diets. Two SOD isoforms, Mn-SODII and a Cu/Zn-SODV, were specifically reduced in the liver of the AIN 93 diet fed animals.The clear differences in antioxidant responses observed in the livers of mice fed on the two diets suggest that the macro- and micro-nutrient components with antioxidant properties, including vitamin E, can promote changes in the activity of enzymes involved in the removal of the ROS generated by cell metabolism.Differences in the composition of antioxidant compounds in diets and nutritional supplements are known to cause changes in the responses of enzymes involved in cellular defense mechanisms against free radicals [1,2]. Experimental studies using a commercial diet for rodents as a control diet, revealed a smaller antioxidant response in the control animals when compared to obese animals grown on a high fat diet. It was suggested that such a difference may be due to the amount of vitamins, such as vitamin E in the diet [3]. Under normal metabolic conditions, components of the defense mechanism of the liver, such as the enzymes superoxide dismutase, catalase and glutathione peroxidase, and non-enzymatic antioxidants such as glutathione, vitamin A, C and E, may prevent the accumulation of intracellular free radicals [4] and eventual cellular damage. The presence of vitamins and other nutrients with antioxidant activity, acting in conjunction with antioxidant enzymes has been shown to have beneficial effects against free radicals produced under normal physiological and pathophysiological conditions [5].Alt