Atherosclerosis in rats induced by repeated breedings, ACTH and unilateral nephrectomy. Acid mucopolysaccharides, fibroplasia, elastosis and other changes in early lesions.

Repeatedly-bred rats of both sexes develop subintimal accumulations of acid mucopolysaccharides and fibroblastic proliferation followed by distortion and destruction of elastic lamellae. Fibrosis, endothelial hyperplasia, lipid deposition, calcification and atheromata are also observed. Changes in the elastic tissue occur independently, and later than the alterations of the ground substance and the fibroblasts. Calcification is found in more advanced lesions, showing an affinity for areas rich in mucopolysaeeharides. Exogenous ACTH and unilateral nephrectomy augment early atherosclerotic changes associated with multiple breedings.