The neovascularization in ischemic myocardium by bone marrow stromal cells transplanting and its impact on cardiac function

Objectives To investigate the neovascularization of ex vivo expanded bone marrow stromal cells (MSCs) in ischemic myocardium and its effects on cardiac function. Methods Myocardial infarction was induced by ligating the left anterior descending coronary artery of the rabbits. Three days later, the isolated and cultured MSCs were labeled with the fluorescence tracer DAPI, and then transplanted respectively into the ischemic myocardium of itself (transplantation group, n=8), other rabbits received equal culture media (control group, n=6). 4 weeks later, the echocardiography was performed to analysis the left ventricular ejection fractions (EF) and fraction shorting (FS). Then, the myocardium was harvested. Fluorescence tracing was used to determine the survival of the transplanted MSCs in the ischemic myocardium. Immunohistochemical staining was used to analysis the capillary density. Results The implanted MSCs were found in the ischemic tissue and within the wall of small vessels in the area adjacent to myocardial infarction by fluorescence microscope; The capillary density was significantly greater in MSCs group than that in the control group [(163.00±25.85) vs (96.00±16.61),P0.05]; In the control group, the capillary were found only in the ischemic area, however in the transplantation group, the capillary were found both in the ischemic and the infarct area. The EF and FS in the transplantation group was higher than that in the control group EF[(0.50±0.03) vs (0.46±0.03), P0.05]; FS[(27.02±1.27) vs (23.85±1.69), P0.05]. Conclusions Ex vivo expanded MSCs can promote neovascularization of the ischemic myocardial and improve cardiac function.