Changes in chemical and metabolic properties of rabbit aorta by dietary cholesterol, and saturated and polyunsaturated fats

Abstract

Rabbits were given a control diet (group I), or diets containing 1% cholesterol (group 11), 1% cholesterol + 5% coconut oil (group III), or 1% cholesterol + 5% corn oil (group IV). Then the area covered with aortic plaque, the intima/media lipid content, oxygen consumption and glycolytic activity as well as [ 14C]acetate incorporation into aortic lipid fractions were examined. Diets of groups II and III resulted in a markedly greater extent of atherosclerosis as judged by the area covered with aortic plaque and by the lipid content ( P < 0.05) than did the polyunsaturated diet IV. Concomitantly we observed a doubling of aortic oxygen consumption in groups II and III, in contrast with the “normal” values of group IV ( P < 0.01). Glucose consumption was somewhat lower in all atherosclerotic groups as compared with the control group, whereas the glycolytic rate was increased in aortae of groups II and III. Incorporation of [ 14C]acetate was highest in the phospholipid fraction of all groups. In the highly atherosclerotic groups II and III, labelling of unesterified cholesterol seemed to be suppressed ( P < 0.05) in the thoracic part, but cholesterol synthesis de novo was probably negligible. Together with our previously reported findings on lipoprotein properties and metabolism, these data on aortic metabolism may be related to the marked reduction of atherosclerosis in rabbits given a diet containing polyunsaturated fat.