The arterial smooth muscle cells (SMC)are the predominant type of cells within atherosclerotic(As)lesions,and their proliferation plays an important role in the process of As genesis.On the basis of the establishment of primary culture and sub-culture method for human arterial SMC,the effects of LDL, VLDL,HDL,OX-LDL,OX-VLDL, OX-HDL on DNA synthesis of cultured human arterial SMC wereobserved.Results are as follows:(1) HDL had no stimulating effect on ³H-TdR incorporation into DNA of SMC (P>0.05),(2) LDL and VLDL showed the obvious stimulating effects (P<0.05);(3) OX-LDL, OX-VLDL and OX-HDL increased siginificantly ³H-TdR incorporation into SMC DNA, respectively (P<0.01). These results suggest that the atherogenic roles of LDL, VLDL, OX-LDL, OX-VLDL, OX-HDL are closely related to their stimulating effects on DNA synthesis and the proliferation of the arterial SMCs.