Establishment of a rat model with diet-induced coronary atherosclerosis.

Coronary atherosclerotic disease is a serious disease in humans, but no suitable animal model is available currently for further studies. We used apolipoprotein E gene knockout (ApoE KO) rats to induce hypercholesterolemia through a special high cholesterol/bile salt diet (Paigen diet), then analyzed aortic and coronary atherosclerosis lesions and the myocardial injury in order to establish a novel small animal model of coronary atherosclerosis. Plasma cholesterol of ApoE KO rats increased 7.6-fold compared with wild-type rats after 8 weeks on the Paigen diet. After 10 to 12 weeks of subsisting on the Paigen diet, ApoE KO rats developed mild aortic atherosclerosis with severe coronary atherosclerosis. Hematoxilyn and eosin staining showed that 11 out of 12 ApoE KO male rats had right coronary artery atherosclerosis, 7 of them were>70% occluded. Oil Red O (Lipid Stain), Mac2 immuno-staining and Masson's trichrome staining demonstrated substantial amounts of lipid, macrophages and collagen fibers in coronary atherosclerosis plaques. In addition, ApoE KO male rats had severe myocardial focal lesions with cholesterol ester as the main component in the lesions. In conclusion, ApoE KO rats developed severe hypercholesterolemia, coronary atherosclerosis and myocardial cholesterol ester deposition after subsisting on the Paigen diet and can be used as a novel animal model for studies on cholesterol metabolism and coronary atherosclerotic disease.