Aim To understand whether low density lipopro-teins (LDL).very low density lipoprotein(VLDL),especially oxidized low density lipoprotein(ox-LDL)and oxidized very low density lipoprotein(ox-VLDL)have effects on the expression of monocyte chemoat-tractant protein-1(MCP-1)mRNA and protein in cul-tured calf aortic smooth muscle cells(SMCs).Methods After a 24-hour exprosure to LDL,ox-LDL,VLDL and ox-VLDL respectively.the total RNA in calf aortic SMCs was extracted by using the guanidinium isothiocyanate method.The MCP-1mRNA expression in SMCs was examined by slot blot analysis using a γ-32 p-end-labeled 35 mer oligonu-cleotides probe of MCP-1.Meanwhile,MCP-1 pro-tein content in the SMC conditioned media(SMC-CM)of each group was determined by sandwich ELISA.Results Cultured calf aortic SMCs were able to ex-press MCP-1 mRNA and protein,the lever of MCP-1mRNA in SMCs and the concentration of MCP-1 pro-tein in SMC-CM were increased significantly after a 24hour-exposure to ox-LDL and ox-VLDL,respective-ly,whereas the expression of MCP-1 mRNA and pro-tein was only slightly increased when exposed to LDL and VLDL.Conclusion ox-LDL and ox-VLDL can induce a strong expression of MCP-1 in cultured SMCs.