MEASUREMENT OF REACTIVE OXYGEN SPECIES BY CHEMILUMINESCENCE IN DIET-INDUCED ATHEROSCLEROSIS - PROTECTIVE ROLES OF VITAMIN-E AND PROBUCOL ONDIFFERENT RADICAL SPECIES

We have investigated the effects of a high-cholesterol diet on the pro duction of different reactive oxygen species in rabbit aortic rings an d evaluated the protective effects of vitamin E and probucol in preven ting peroxidative changes. Twenty-five male albino rabbits were divide d into five groups. Control rabbits were fed a vitamin E-poor rabbit c how. Rabbits in the second group were given a vitamin E-poor diet supp lemented with 2% cholesterol. Other groups received either 50 mg/kg vi tamin E, 1% probucol, or both, in addition to 2% cholesterol for 4 wee ks. Reactive oxygen species formation in aortic rings was measured by enhanced chemiluminescence using luminol and lucigenin. (The results w ere given as cpm/mg wet weight.) Further differentiation of radical sp ecies involved in luminol-enhanced chemiluminescence was performed usi ng sodium azide and L-nitroarginine, a selective inhibitor of nitric o xide production. Our results indicated that cholesterol feeding increa sed lucigenin and luminol chemiluminescence, where the contribution of free radicals inhibited by sodium azide (radicals originating from en dothelial cells or from phagocytes) were 53% and peroxynitrite 24%. Bo th vitamin E and probucol were effective as scavengers of free radical s, but the effect of vitamin E was more pronounced. In conclusion, the present study demonstrated excessive generation of reactive oxygen sp ecies within the atherosclerotic vessel. Peroxidative changes could be prevented by vitamin E and probucol treatment, but vitamin E seemed t o be more efficient.