Objective To study the short and medium term effect of myocardial contractile force by implantation of endothelial progenitor cells （EPCs） in the myocardial infarction model. Methods Hundred and twenty SD rats were equally and randomly divided into experimental group and control group （60 rats in each group）. Acute myocardial infarction model was created by ligation of LAD. Autologous EPCs were purified from peripheral blood then implanted into the acute myocardial infarct site via topical injection. IMDM were used in control group. Specimens and muscle strip were harvested at 3, 6 weeks, 6, 8 and 12 months after EPCs implantation for contractile force study and to detect the expression of vascular endothelial growth factor（VEGF）, basic fibroblast growth factor （bFGF） and Ⅷ factor by immunohistology and video image digital analysis system. Results The expression of VEGF, bFGF and the microvessel counts in experimental group were much higher than those of control group（P〈 0.01） at 3, 6 weeks and 6 months after transplantation. The contractile force in experimental group was better than that in control group（P〈0.01） at the same time. But from 8 months after implantation, the contractile force and so on were not up in the experimental group. Conclusion EPCs, after being implanted into infarct myocardium, shows the ability of improvement of the contractile performance in infarcted myocardium by means of angiogenesis and vasculogenesis and the medium term results are persistent.
Objective To study the influence of autologous bone mesenchymal stem cells (BMSCs) on myocardial structure and cardiac function after being implantated into acute infarcted myocardial site. Methods Bone marrow was aspirated from the posterosuperior iliac spine of Guizhou Xiang swine. After being isolated, cultured and co cultured with 5 azacytidine, either autologous BMSCs (total cells 2×10 6, experimental group, n =12), or a comparable volume of culture medium (control group, n =12), was injected into the left anterior descending(LAD) branch of coronary artery just distal to the ligation site of the LAD. The same volume of BMSCs or culture medium was injected into several spots in the infarcted myocardium. Echocardiographic measurements were performed three or six weeks after implantation to assess the myocardial structure and cardiac function. Results Left ventricular function, including eject fraction(EF), fractional shortening and wall thickening, were higher in experimental group when compared with control group. The thickness of the ventricular wall and septum was also found increased while the left ventricular chamber size was smaller in experimental group. Conclusion Implantation of BMSCs into the infarcted myocardium is believed to attenuate the remodeling process, inhibit the extent of wall thinning and dilatation of the ventricular chamber. BMSCs implantation may also improve the contractile ability of the myocardium and cardiac function.
