ANTIOXIDANT STATUS OF JAPANESE-QUAIL - COMPARISON OF ATHEROSCLEROSIS-SUSCEPTIBLE AND ATHEROSCLEROSIS-RESISTANT STRAINS

OBJECTIVE: To compare levels of antioxidant components of blood and ao rtic tissue from two strains of Japanese quail showing high and low su sceptibilities to atherosclerosis and receiving either control or chol esterol-enriched diets. ANIMALS: All experimental birds were placed on the control diet until eight weeks of age. Twenty males of each strai n were then placed on the atherogenic diet (control diet supplemented with 1% cholesterol) and another 20 males of each strain were continue d on the control diet for an additional 10 weeks. MAIN RESULTS: In the absence of cholesterol supplementation, plasma cholesterol and trigly ceride and antioxidant enzyme profiles of aorta, red blood cells and p lasma were comparable in the two groups of birds, with the exception o f a small, but significant (P<0.05), decrease in aortic glutathione re ductase in susceptible animals (0.378 nmol/min/mg) relative to the res istant birds (0.441 nmol/min/mg). Cholesterol feeding produced larger increases in cholesterol and triglycerides and more extensive atherosc lerotic plaque formation in susceptible compared with resistant quail. In the susceptible group, significant negative correlations were note d between severity of atherosclerotic lesions and aortic superoxide di smutase (correlation coefficient -0.752) and glutathione reductase (co rrelation coefficient -0.775) activities. Cholesterol feeding was asso ciated with increased activity of plasma glutathione peroxidase and su peroxide dismutase activities in both strains, although only the susce ptible birds showed significant positive correlations of superoxide di smutase activities with plasma cholesterol (correlation coefficient +0 .694) and triglycerides (correlation coefficient +0.669). Peroxide-ind uced depletion of glutathione in red blood cells was unaffected by cho lesterol feeding, although red blood cell susceptibility to lipid pero xidation was decreased to an equivalent degree in both strains. CONCLU SIONS: Susceptible and resistant quail are biochemically distinct in t erms of alterations in antioxidant components produced by dietary chol esterol supplementation. Results of the present study are consistent w ith the proposed involvement of oxidative processes in the pathogenesi s of atherosclerosis.