Aim To investigate the effect of amlodipine on the expression of Cyclophilin A in smooth muscle cells induced by oxidized low density lipoprotein(ox-LDL),so as to approach the mechanism of amlodipine in atherosclerosis.Methods Smooth muscle cells were treated with ox-LDL in different concentration or different time.Based on that,the cells were pretreated with amlodipine at different concentrations(0,0.1,1.0 and 10.0 μmol/L) and then incubated with ox-LDL,RT-PCR and Western blotting were used to detected the expression of Cyclophilin A in the cells.Results The expression of Cyclophilin A in smooth muscle cells induced by ox-LDL was obviously up-regulated by amlodipine in a dose-dependent manner.Conclusion Amlodipine may reverse the role of ox-LDL on the Cyclophilin A expression in smooth muscle cells.