MORPHOLOGIC AND FUNCTIONAL-CHANGES OF THE AORTIC INTIMA DURING EXPERIMENTAL-HYPERTENSION

Abstract

The morphology and permeability to horseradish peroxidase of the rat aortic intima were investigated in 3 experimental models of hypertension having different values of plasma renin content and plasma aldosterone level. During hypertension the aortic endothelium shows the following 3 main changes: increased arithmetic mean thickness, with prominent rough endoplasmic reticulum and polyribosomes; the appearance of actin microfilament bundles; and increased permeability to horseradish peroxidase. These changes are not present in all models, do not appear to depend on hypertension per se and are independent of each other. The subendothelial layer of hypertensive animals shows an increased thickness that appears to be correlated with an increase of endothelial cell volume. The aortic intima apparently reacts differently to different types of hypertension, and factors other than hypertension per se play a role in the development of vascular changes observed in animals with elevated blood pressure.