Aim To investigate the effects of basic fibroblast growth factor(bFGF)on the DNA synthesis of vascular smooth muscle cells(VSMC)and the expression of genes related to cell proliferation.Methods The effects of basic fibroblast growth factor on the DNA synthesis was studied by means of 3H-TdR incorporation c-fos,c-myc and proliferating cell nuclear antigen (PCNA) mRNA were displayed by Northern blot and reverse transcription polymerase chain reaction (RT-PCR) respectively.Results The results indicated that R-TdR incorporation into VSMC began increased in 6 h after addition of bFGF, and reached a peak in 24 h. VSMC DNA synthesis was induced by bFGF in a dose dependent manner in certain range of concentrations. The maximal expression of proto-oncogenes c-fos and c-myc mRNA was observed at 1 h after addition of the cytokine.PCNA mRNA expression occured twice in a cell cycle.Conclusions our findings demonstrated that bFGF may significantly stimulate DNA synthesis of VSMC,and suggested that increase in VSMC DNA synthesis was followed by the expression of proto-oncogenes c-fos and c-myc,which is believed as key step in cell proliferating.