目的　探讨纤溶酶原激活物抑制剂 - 1(plasminogen activator inhibitor- 1,PAI- 1)反义 RNA对离体培养的主动脉平滑肌细胞 (smooth muscle cell,SMC) PAI- 1表达的作用及对血管内皮生长因子(vascular endothelial growth factor,VEGF)表达的影响。方法　PCR扩增 PAI- 1第 2外显子 ,将 PCR产物纯化克隆后连入真核细胞表达载体 pc DNA3.1,构建 PAI- 1反义 RNA重组质粒。将 pc DNA3.1-反义PAI- 1重组质粒转染 SMC中。通过免疫组化、Western印迹、EL ISA检测细胞中 PAI- 1表达的改变 ;通过免疫荧光技术观察细胞中 PAI- 1表达量的变化对 VEGF的影响。结果　转染后第 3天 ,细胞中 PAI- 1含量最低 ,VEGF的表达也减少。第 5天 ,PAI- 1含量逐渐升高 ,VEGF也相应增加。第 7天 ,PAI- 1含量接近于正常 ,VEGF也增至正常水平。结论　反义 PAI- 1RNA能有效阻断 SMC中 PAI- 1的蛋白合成 ,同时抑制细胞中 VEGF的表达。 Objective To investigate the effect of plasminogen activator inhibitor-1 (PAI-1) antisense RNA on the expression of PAI-1 in cultured aortic smooth muscle cells (SMC) Effect of vascular endothelial growth factor (VEGF) expression. Methods The exon 2 of PAI-1 was amplified by PCR. The PCR product was cloned into the eukaryotic expression vector pcDNA3.1 to construct PAI-1 antisense RNA recombinant plasmid. The pcDNA3.1-antisense PAI-1 recombinant plasmid was transfected into SMC. The changes of PAI-1 expression in cells were detected by immunohistochemistry, Western blot and ELISA. The effect of PAI-1 expression on VEGF was observed by immunofluorescence. Results On the 3rd day after transfection, the content of PAI-1 was the lowest and the expression of VEGF was also decreased. On the fifth day, the content of PAI-1 gradually increased and the VEGF increased accordingly. On day 7, PAI-1 levels approached normal, and VEGF also increased to normal levels. Conclusion Antisense PAI-1RNA can effectively block the protein synthesis of PAI-1 in SMC and inhibit the expression of VEGF in SMC.