Cryodamage of the vessel wall accelerates the development of atherosclerotic lesions in arterial vessels of Watanabe hyperlipidemic rabbits

In the present study we developed an experimental model, resembling human atherosclerosis, by removing the endothelial layer in Watanabe heritable hyperlipidemic (WHHL) rabbits (10 months old) by application of cryodamage on the external surface of arterial vessels. In age-matched New Zealand white (NZW) rabbits, used as control, after two months following cryodamage, carotid artery and infrarenal segments of abdominal aorta did not show any particular change in the ultrastructure of vessel wall. In WHHL rabbits, two months after cryodamage, atherosclerotic lesions (fatty streaks and fibrous plaques) were observed in both arteries. Many lipid-laden endothelial cells, subendothelial foam cells and smooth muscle cells were found in cryodamaged areas. In some areas, the cap of plaques appeared to be thinned and ruptured. Increased number of collagen and elastic fibrils was also observed in atherosclerotic regions. We conclude that this simple technique on WHHL rabbits provides a model of atherosclerosis with a high degree of morphological similarity between the artificially-induced plaque and human atherosclerotic plaque