A quantitative study of the development of sudanophilic lesions in the aorta of rabbits fed a low-cholesterol diet for up to six months.

Eighteen New Zealand white rabbits were placed on a diet containing 0.25% cholesterol and 6% corn oil for periods of up to 6 months. The animals were divided into 4 gours and sacrificed after 2, 3, 4, and 6 months. The aortae were removed, stained with Sudan III, and analyzed with the polar coordinate technique. While the periorificial lesions developed more slowly on this diet than on the diet with 2% cholesterol and 6% corn oil we had used previously, there was no differences in either the location or the shape of the lesions. In the descending thoracic aorta, lesions developed initially distal to orifices; however, significant lateral and proximal components were observed as atherogenesis progressed. The coronary lesions completely surrounded the ostia in all stages of development. The total area of the lesions was more related to time (r = 0.74, P less than 0.01), than to serum cholesterol (r - 0.51, P less than 0.05) or to cholesterol-time product (r = 0.69, P less than 0.01).