Epidemiological studies suggest that an increase of diesel exhaust particles (DEP) in ambient air corresponds to an increase in hospital recorded myocardial infarctions and atherosclerosis after exposure.However, the detail by how DEP cause endothelial cells death remains unclear.To elucidate the mechanism, we used a human umbilical vein endothelial cell (HUVEC) culture model system.Automobile DEP were resuspended then added immediately at 25 and 50 μg/mL medium-diluted DEP solution to the dishes.