AimTo construct a lentivirus vector expressing microRNA (miRNA) Rno-miR-145 and probe function of the vector in platlet derived growth factor (PDGF) induced vascular smooth muscle cells(VSMC) phenotype transform.MethodsThe miR-145 shDNA double chain template sequence was synthesized artificially and put this template sequence clone LV3 pGLV/H1/GFP+Puro-miRNA Lentivirus plasmid.293T cells were transfected.Lentivirus particles(virosome) were harvested and concentrated, then primary cultured VSMC of the rats were infected.Fluorescence expression infected with VSMC was observed by inverted fluorescence microscope.miR-145 expression condition was detected with real-time PCR.Blank control group,PDGF group, PDGF＋miR-145 group and miR-NC group were divided in this test.Influence of miR-145 on related genes c-Jun,PCNA,SM22α expression level was observed with real-time PCR.ResultsmicroRNA-145 lentivirus plasmid was construted successfully.The viral titer was 1×109TU/mL.microRNA-145 lentivirus expression plasmid was infected successfully.The best transfection efficiency was on the 3th day when multiply infection(MOI) was 50.Real-time PCR results revealed PDGF increased PCNA,c-Jun expression level,but reduced SM22α expression; miR-145 made VSMC related genes PCNA,c-Jun expression reduce,but made SM22α expression increase.ConclusionMicroRNA-145 lentivirus plasmid may infect rat VSMC efficiently.VSMC phenotype transformation may be inhibited by microRNA-145.