Morphological evaluation of the atherogenicity of corn oil, hydrogenated corn oil, and butter fat in quail.

The atherogenicity of corn oil, hydrogenated corn oil, and butter fat was studied using 57 fourty-day-old male Japanese quails. The animals were fed one of the following diets: basal diet, basal diet with corn oil plus cholesterol, basal diet with hydrogenated corn oil plus cholesterol, or basal diet with butter fat plus cholesterol. Each atherogenic diet contained 15% fat and 2% cholesterol. Marked hypercholesterolemia developed in all fat-fed groups after 3 weeks or 3 months, but no significant difference was seen among the groups. The degree of the luminal narrowing of the ascending aorta and brachiocephalic arteries was highest in the corn oil group and lowest in the hydrogenated fat group. Ultrastructurally, all the fat-fed groups showed similar cellular changes in their aortic lesions. The major cell type of the thickened intima was fibroblast-like cells with or without lipid droplets. Immunohistochemical studies disclosed that alpha-1-antichymotrypsin was strongly positive for fibroblast-like cells in the thickened intima, whereas it was negative for those in the tunica media of the ascending aorta and its branches. These data suggest that hydrogenated corn oil has a less potent stimulating effect on the thickening of the arterial intima than corn oil and butter fat.