AORTIC ANTIOXIDANT DEFENSE AND LIPID-PEROXIDATION IN RABBITS FED DIETS SUPPLEMENTED WITH DIFFERENT ANIMAL AND PLANT FATS

Objective: To test the hypothesis that dietary fats, depending on the fat source, may modulate aortic lipid peroxidation and antioxidant pro tection. Methods: Rabbits were fed a low fat (LF, 2 g/100 g corn oil) diet or LF enriched with 16 g/100 g (w/w) of corn oil (GO), corn oil p lus cholesterol (23.5 mg/100 g diet, CO+C), bovine milk fat (MF), chic ken fat (CF), beef tallow (BT) or lard (L). After a 30-day feeding per iod, aortic lipid peroxidation, as well as antioxidant enzymes and vit amin E were measured. Results: In rabbits fed CO or L, aortic TEARS (a marker of lipid peroxidation) and total glutathione concentrations we re greater but vitamin E levels were lower compared with the LF treatm ent. Moreover, in rabbits fed CO, elevated activities of glutathione p eroxidase and glutathione reductase but lowered activity of superoxide dismutase were observed. In rabbits fed the remaining high fat diets, including the CO+C diet, aortic lipid peroxidation and antioxidant ac tivities/levels did not differ from those fed LF. Feeding rabbits high -fat diets for 30 days did not induce aortic lipid deposition. Conclus ions: The present results indicate CO, and possibly L, as the fat sour ces which significantly increase aortic oxidative stress. Because long -term disturbances in redox status may be implicated in atherogenesis, excessive dietary intake of CO or L may significantly contribute to t he injury of the vessel wall.