Abstract
The aorta is a blood vessel in which atherosclerosis occurs frequently. The blood pumped out from the heart flows inside the aorta in a varying direction as it travels along the ascending aorta, aortic arch, and descending aorta. In a vessel of such curvature, secondary flow inevitably occurs, causing a change in the distribution of shear stress in the vessel. It seems that, due to these factors, the endothelial cells are injured so that their permeability increases, leading to the deposition of lipid and protein on the vascular wall and, eventually, to atherosclerosis.
In the present study, we prepared rabbits with hypercholesterolemia induced by a 1% cholesterol diet, and investigated the relationship between the site of initial atherosclerotic lesions and the secondary flow or the distribution of shear stress in the animals under constant-pressure perfusion fixation. As a result, in the area from the aortic arch to the descending aorta in hypercholesterolemic rabbits, a high incidence of cholesterol deposits and atherosclerosis was found to coincide with the inner side of the vessel, where the shear stress was minimal.
