Abstract
The antiatherosclerotic effect of lacidipine has been attributed to its actions on cholesterol levels, lipid metabolism or oxidant stress in advanced disease. The purpose of the present experiments was to examine whether lacidipine is protective of intimal thickening and vascular dysfunction in early atherosclerosis in the absence of the hypertension and hypercholesterolemia. A second goal was to determine whether and to what extent MMP-9 and oxidant stress are involved in possible beneficial effects of lacidipine. Lacidipine treatment (5 mg/kg/day, p.o. for 3 weeks) significantly prevented the collar-induced intimal thickening. MMP-9 expressions were increased by collar but not effected by lacidipine treatment. Nitrotyrosine staining, a marker for oxidant stress was not changed neither by collar nor lacidipine treatment in early atherosclerosis. The enhanced sensitivity to serotonine and diminished sensitivity to acetylcholine in collared arteries were restored to normal levels with treatment. These results demonstrate that the lacidipine treatment prevents the collar-induced intimal thickening and accompanying vascular dysfunction in early atherosclerosis without cholesterol loading. These beneficial effects of lacidipine were not associated with changes in either MMP-9 expression or oxidant stress. However, enhanced endothelium-dependent relaxations by lacidipine, suggest that vascular protective effects of nitric oxide may be at least partly, responsible from antiatherosclerotic effects of lacidipine.