目的探讨同型半胱氨酸(homocysteine,Hcy)促进人主动脉平滑肌细胞(HASMC)的增殖作用及其分子机制。方法透射电镜观察HASMC增殖的形态学变化;MTT法测定Hcy对HASMC的增殖作用;Western blot法和荧光定量反转录PCR法分别检测PI3K、p-Akt和Egr-1蛋白及mRNA的表达水平。结果 Hcy处理HASMC 48 h后,细胞内均出现空泡增多、内质网扩张和线粒体固缩的现象,对照组细胞形态正常。随着Hcy浓度的增高,与对照组比较,OD值逐渐增高,当Hcy浓度固定时,48 h OD值较24 h升高,差异有统计学意义(P<0.05)。PI3K、p-Akt和Egr-1蛋白相对表达水平随着Hcy浓度的增加而逐渐升高,差异有统计学意义(P<0.05)。PI3K、p-Akt和Egr-1 mRNA表达水平较对照组均显著升高,差异有统计学意义(P<0.05),且PI3K和Akt mRNA表达水平的增加与Hcy呈浓度依赖性(P<0.05)。结论 Hcy可通过增强PI3K/Akt信号通路关键蛋白和分子表达,促进早期生长反应因子Egr-1的转录及翻译,诱导人主动脉平滑肌细胞迁移、增生,加速动脉粥样硬化发生。 Objective To investigate the effect of homocysteine ​​(Hcy) on the proliferation of human aortic smooth muscle cells (HASMC) and its molecular mechanism. Methods The morphological changes of HASMC proliferation were observed by transmission electron microscopy. The proliferation of HASMCs was detected by MTT assay. The protein and mRNA expressions of PI3K, p-Akt and Egr-1 were detected by Western blot and fluorescence quantitative reverse transcription PCR. Results After treated with Hcy for 48 h, the vacuoles, endoplasmic reticulum dilation and mitochondria shrinkage were observed in the cells. The cells in the control group were normal. With the increase of Hcy concentration, the OD value gradually increased compared with the control group. When Hcy concentration was fixed, the OD value at 48 h was higher than that of the control group (P <0.05). The relative expression of PI3K, p-Akt and Egr-1 protein increased with the increase of Hcy concentration, the difference was statistically significant (P <0.05). The mRNA expression of PI3K, p-Akt and Egr-1 were significantly higher than that of the control group (P <0.05), and the increase of PI3K and Akt mRNA was correlated with the concentration of Hcy in a concentration-dependent manner ). Conclusion Hcy can promote the migration and proliferation of human aortic smooth muscle cells and accelerate the development of atherosclerosis by enhancing the expression of key proteins and molecules of PI3K / Akt signaling pathway, and promoting the transcription and translation of Egr-1, an early growth response factor.