Aim To observe the protein expression of Cyclophilin A in lipid-loaded macrophages induced by oxidized low density lipoprotein and its effect on cellular cholesterol accumulation.Methods RAW264.7 mouse macrophages were treated with 75 mg/L oxidized low density lipoprotein(ox-LDL) for different time(control,24 hours,48 hours and 72 hours).Western-blot analysis and immunofluorescence were used to detect protein expression of Cyclophilin A.High performance liquid chromatography(HPLC) analysis was peformed to determine the content of cellular total cholesterol and cholesterol ester.Results Western-blot analysis and immunofluorescence showed that the protein expression of Cyclophilin A was significantly decreased in a time-dependent manner in macrophages.High performance liquid chromatography(HPLC) analysis was peformed the content of cellular total cholesterol and cholesterol ester were increased greatly.Conclusions The protein expression of Cyclophilin A was down-regulated in lipid-loaded macrophages while the content of cellular total cholesterol and cholesterol ester were increased greatly.