Aim To investigate the effect of cigarette smoke extract(CSE) on the proliferation of vascular smooth muscle cells(VSMC) and the relevant roles of basic fibroblast growth factor(bFGF). Methods(1)The rat aortic smooth muscle cells were treated with various concentrations of cigarette smoke extract(0%,2.5%,5.0%,10.0%,20.0%),the VSMC treated without CSE were control group,then MTT assay was performed to observe the changes of the proliferation of VSMC.The expression of proliferating cell nuclear antigen(PCNA) and Fibroblast Growth Factor 2(bFGF) were detected by immunocytochemistry.In addition,reverse transcription polymerase chain reaction(RT-PCR) was applied to detect the mRNA expression of bFGF.(2)Treated with 5%CSE(the optimal concentration) at 0 h(control group),4 h,8 h,12 h,24 h,the expression of bFGF mRNA,bFGF and PCNA protein were observed.(3)Treated with bFGF antibody and 5.0%CSE at 24 h,MTT A value,bFGF and PCNA protein were observed. Results(1)CSE can stimulate the increase of MTT absorbance(A)value.The absorbance(A)value of 2.5%(P><0.05),5.0%CSE(P><0.01) group were significantly increased compared to the control group.The absorbance(A)value of 10%,20%CSEgroup were not significantly increased compared to the control group(P>0.05).There was the maximal increase in5.0% CSE group.The VSMC in control group expressed bFGF mRNA,bFGF and PCNA protein at low levels.In-creased bFGF mRNA,bFGF and PCNA protein expression were evident after 2.5%CSE treatment.Maximal increase inbFGF mRNA,bFGF and PCNA protein expression occurred after5.0%CSE treatment.Then expression were still elevat-ed compared with control group’s after 10%,20%CSE treatment.(2)The VSMC in control group expressed bFGF mR-NA,bFGF and PCNA protein at lowlevels.Increased bFGF mRNA,bFGF and PCNA protein expression were evident at4h after CSE treatment.Maximal increase in bFGF mRNAoccurred at8 h,while peak expression of bFGF and PCNApro-tein was at12 h.(3)Treatment with bFGF antibody nearly inhibited CSE-induced MTTA value,bFGF and PCNA proteinexpression.Conclusion The proliferation of VSMC increased gradually in low and middle concentrations(2.5%,5.0%CSE group),while decreased in high and higher concentrations(10%,20%CSE group)on the contrary.CSE maybe in-creased rat VSMC proliferation by high expression of bFGF.