MACROSCOPIC DISTRIBUTION OF CORONARY ATHEROSCLEROTIC LESIONS IN CHOLESTEROL-FED RABBITS

In the present study we macroscopically examined a change in the distr ibution of coronary atherosclerosis in cholesterol-fed rabbits. Rabbit s were fed a cholesterol-enriched diet for 15 weeks, then replaced by a normal diet, and were sacrificed at 15, 24, 32 and 42 weeks after th e start of the experiment. The coronary atherosclerosis in the cholest erol-fed rabbits was distributed more densely in the proximal portion than in the middle and distal portions, and the lesions were severe at 24 and 32 weeks after the start of the experiment. Comparison of lesi ons in the three portions at these time points showed that the percent ages of lesion areas in the proximal portion, the middle portion and t he distal portion were approximately 51%, 21 to 25% and 0.2 to 3.7%, r espectively. Macroscopic observation of the coronary atherosclerotic l esions showed that the lesions formed over the vessel lumen in the pro ximal portion within the range of approximately 5 mm from the orifice of the left coronary artery. In the middle portion, the lesions formed predominantly around the orifices of branches as small patchy lesions from 1 to 3 mm in diameter. These findings support previous histopath ological reports that suggested that the incidence of stenosis in the proximal portion was high, and the incidence of lesion occurrence in t he middle and the distal portions varied. The method, macroscopical in vestigation of the coronary artery, is useful for analyzing coronary a therosclerosis in the rabbit.