[The effects of captopril in arterial proliferative response after intima balloon denudation]

We studied the effects of angiotensin-converting enzyme inhibitor on the response of arterial intima after balloon denudation. Captopril (3 mg.kg-1/d) was administered to 4 miniature pigs after abdominal aortic balloon denudation. As controls, 4 pigs were only denuded abdominal aorta without using captopril. All animals were given high cholesterol diet immediately after abdominal aortic denudation. At the end of the 6th and 10th month, 8 pigs were sacrificed equally in two times. Irregular protrusion of arterial wall was observed in all animals at gross anatomy. In the control group, the atherosclerotic plaque was identified via sudan stains. The neointima proliferative response after arterial denudation was found, but the degree of neointima proliferation at captopril group was significantly decreased as compared to non-captopril group (P < 0.01). Microscopic examination showed smooth muscle cell proliferation of arterial neointima in non-captopril group, while slight connective tissue proliferation in captopril group. Electronmicroscopically endothelial cells showed protrusion and their connective gap was increased in the control group. Many platelets were adhered to the arterial neointima, the smooth muscle cells were mainly of secretary type in the same group. The endothelial cells were normal, smooth muscle cells of the neointima were mainly of contractile type in the captopril group. These results illustrate that angiotensin-converting enzyme inhibitor inhibits the proliferative response after arterial intima denudation, on the other hand, angiotensin-converting enzyme may play an important role in neointima proliferative response after intima injury.