胎儿心肌细胞移植重建大鼠梗死心肌

目的　探讨将胎儿心肌细胞移植到心肌梗死后大鼠心肌重建的可行性及效果。方法18只雄性Wistar大鼠经左冠状动脉前降支永久性结扎建立前壁心肌梗死模型 (MI组 ) ,设假手术对照组 6只。胎儿心肌细胞被分离及培养 5d ,证实为活的心肌细胞。大鼠心肌梗死手术后第 5天再分为两组 ,细胞移植组 (7只 ) 2× 10 6心肌细胞注入受体大鼠心肌坏死瘢痕中 ,另一组为培养基注入组 (6只 )。在细胞移植前及细胞移植后 6 0d± 3d中行超声心动图检查 ,评价左心室重构及心功能。然后处死大鼠并收集心脏 ,进行组织学及免疫组化检查 (免疫组化染色抗体为抗人平滑肌α 肌动蛋白 )。结果　光镜显示移植的人的胎儿心肌细胞存活在梗死的心肌中 ,并在胎儿心肌细胞和宿主心肌细胞之间存在闰盘连结。平滑肌α 肌动蛋白通常在胚胎心肌细胞中存在而在成年鼠心肌细胞中不存在 ,移植的细胞通过抗人平滑肌α 肌动蛋白免疫组化染色呈阳性反应得到证实。系列超声心动图研究发现 ,细胞移植阻止了梗死瘢痕心肌变薄、左室进一步扩张及心脏收缩功能恶化。而对照培养基注入组超声心动图显示 ,左室壁瘢痕变薄 ,左室明显扩张 ,左室收缩功能进行性恶化。结论　胎儿心肌细胞可以被移植并在大鼠梗死心肌中存活。胎儿心肌细胞移植到大鼠心肌梗死区域可明

Transplantation of fetal cardiomyocyte regenerates infarcted myocardium in rats

OBJECTIVE: To investigate the feasibility and efficiency of fetal cardiomyocyte transplantation into the rat model of myocardial infarction. METHODS: Cardiomyocytes were isolated from aborted human embryos aged 12 - 16 weeks and cultured for 5 days to confirm their viability. Rat model of extensive myocardial infarction (MI) was established in 18 male Wistar rats by ligating the descending anterior branch of left coronary artery and the 18 rats were randomly divided into 2 groups: transplantation group (n = 7, 2 x 10(6) fetal cardiomyocytes were transplanted into the myocardial scar) and culture medium injection group (n = 6, culture medium was injected into the myocardial scar) 5 days after extensive MI was caused. Another 6 rats undergoing sham operation were used as controls. Echocardiography was performed before and 60 +/- 3 days after the implantation to assess the left ventricular (LV) remodeling and cardiac function. Then the rats were killed and their heart were harvested to undergo HE staining, immunohistochemical examination with antibody against human alpha-actin smooth muscle (SMA) isoform, and light microscopy. RESULTS: Light microscopy revealed the presence of engrafted human fetal cardiomyocytes in the infarcted myocardium and the presence of nascent intercalated disks connecting the engrafted fetal cardiomyocytes and the host myocardium. The engrafted fetal cardiomyocytes were SMA positive. Serial echocardiography revealed that cell transplantation prevented scar thinning, LV further dilatation and dysfunction while the control animals developed scar thinning, significant LV dilatation accompanied by progressive deterioration in LV contractility. CONCLUSION: Fetal cardiomyocytes can be implanted and survive in the infarcted myocardial cells, thus preventing the scar thinning, and LV further dilatation and dysfunction.