Aortic oxidative stress in methionine-induced atherosclerosis in rabbits

Methionine may induce lipid peroxidation and exert atherosclerotic effects. To test this hypothesis, plasma and aortic thiobarbituric acid reactive substances (TEARS), as well as activities of aortic and erythrocyte Superoxide dismutase (SOD), catalase and selenium-dependent glutathione peroxidase (OPX) were measured in rabbits fed a diet enriched with 0.3% tnethionine for 6 or 9 months. Histological examinations of aortas also were performed. Feeding rabbits a methionine-enriched diet for 6 or 9 months resulted in significant increases in plasma and aortic TEARS levels and aortic antioxidant enzyme activities. However, a decrease in plasma AOA was observed. In erythrocytes, SOD activity increased, catalase remained normal and GPX decreased in the treated animals. Histological examination of aortas showed typical atherosclerotic changes, such as intimal thickening, deposition of cholesterol, and calcification in methionine-fed rabbits. These results confirm that high-methionine diet may induce atherosclerosis in rabbits and indicate disturbances in lipid peroxidation and antioxidant processes as possible mechanisms of its atherogenic influence.