OBJECTIVETo evaluate the effects of aspirin, clopidogrel, and their combination on the progression of aortic atherosclerosis.

METHODSForty-nine male rabbits were randomly divided into five groups. One group of control rabbits (group N, n=9) was fed on normal diets. Four other groups were fed on high cholesterol diets and injected with 10% albumin bovine received no drug therapy (group M, n=10), aspirin (group A, n=10), clopidogrel (group C, n=10), or the combination (aspirin+clopidogrel, group B, n=10) for 12 weeks. Serum lipids and C-reactive protein (CRP) were detected. The aortas were harvested for histomorphometry and quantitative analysis. The positive percentage of macrophage cells and smooth muscle cells in the plaque were analyzed by immunohistochemistry.

RESULTSThese antiplatelet drugs significantly reduced the extent of atherosclerosis. Aortic vascular lesions of group A, C, and B showed 28.70%, 28.82%, and 57.69% of reduction in the amount of macrophage cells, and 39.86%, 42.60%, and 100.70% of increase in smooth muscle cells. No significant differences existed between group A and group C. However, the combination of aspirin and clopidogrel had better effect than aspirin or clopidogrel alone. Meanwhile, aspirin, clopidogrel, and their combination also decreased serum CRP (P < 0.05-0.01), without affecting lipid levels. There was a trend, not significantly, to lower serum C-reactive protein in group B compared with group A or group C.

CONCLUSIONSAspirin and clopidogrel inhibit neointimal proliferation and prevent the development of atherosclerosis with equivalent effects. Their combination shows synergic effects.