Objective To study the bovine coronary artery endothelial cells(BCAEC)damage induced by cigarette abstracts and further clarify the relationship between smoking and cardiovascular diseases.Methods BCAEC were treated with nicotine, mainstream smoke extract(MSW)and sidestream smoke extract(SSW)which had the normal concentration(1.0?10~(-5),0.8?10~(-5), 0.9?10~(-5)mol/L)of nicotine in smoker.The morphological changes of BCAEC were recorded by microscope digital image system. The quantification of apoptotic BCAEC cells was performed by visualization of nuclei stained with 4,6'-diamidino-2-phenylindole and trypan blue exclusion assay was used to examine the percentage of necrotic BCAEC.The caspase activity assay was employed to discuss the mechanism of BCAEC apoptosis.Results BCAEC exposed to nicotine and MSW appeared the typical morphological alteration of apoptosis and necrotic morphological alteration were observed after BCAWC were treated with SSW. 5.89% and 11.94% apoptotic ceils were found after BCAEC were exposed to nicotine and MSW for 24 hours.The level of BCAEC necrosis after treated with SSW was 62.84%.Caspase-3 activity was induced by nicotine and MSW.Conclusion Cigarette smoke extract can induce the cell death of BCAEC.Nicotine and MSW can induce caspase-3 activity increase.Even in the presence of a non-cytotoxic concentration of nicotine and mainstream smoke solution,protease-induced apoptosis of BCAEC can be significantly increased.Sidestream smoke solution may cause BCAEC necrosis instead of apoptosis.Caspase-3 activation is probably the mechanism of BCAEC apoptosis.