Abstract: AIM:To explore the pharmacological mechanism oflycopene against atherosclerosis by tumor necrosis factor-α mRNA expression on the myocardial cells and aortic smooth cells.METHODS:AS animal models were randomized into 5 groups with 6 rabbits in each group:The normal groups(N),AS model group(M),the small dose of lycopene group(LS),the large dose of lycopene group(LL),the xuezhikang group(X).The groups were fed with hiigh fatty diet for 60 d except the normal group.Lycopene with different doses or xuezhikang was given by gavage from the 61 d to the end of the experiment.Their doses were:LL[50mg/(kg·d)],LS[16.6mg/(kg·d)],X[56mg/(kg·d)].The blood samples were analyzed for total cholesterol (TC),trigiyceride(TG),high density lipeprotein(HDL),low density lipoprotein(LDL).The TNF-α mRNA expression in the aortic smooth muscle cells and heart muscle cells were detected by using RT-PCR.SPSS 13.0 software was used to evaluate the difference between the 5 groups.RESULTS:Compared with the model group,the TG level was lower markedly by dietary lycopene at the end of the experiment(P<0.05).Lycopene of large dose could decrease the expression level of TNF-α mRNA.witll very significant difference when compared with that of model group. CONCLUSION:Lycopene can down-regulate the LDLR mRNA expression in the induced AS animal models,which implied that lycopene might prevent the occurrence of AS by regulating the TNF-α mRNA expression.