Objective To investigate the therapeutic effectiveness of intracoronary implantation of autologous bone marrow mononuclear cells （BM-MNC） in miniswine model of reperfused myocardial infarction. Methods Sixteen miniswine myocardial ischemic reperfusion injury models made by ligation of the distal one third segment of left anterior descending artery for 90 minutes were randomized into 2 groups. In BM-MNC group （n = 9）

（3.54±0.90）×108 BM-MNC were intracoronary injected

and in the control group （n = 7）

phosphate buffered saline was injected by the same way. Echocardiographic and hemodynamic results

vessel density

and myocardial infarction size were evaluated and compared before and 4 weeks after cell transplantation. Results In BM-MNC group

there were no differences between before and 4 weeks after transplantation in aspects of left ventricular ejection fraction （LVEF）

interventricular septal thickness

left ventricular lateral and anterior septal wall thickness

cardiac output

or +dp/dtmax. In control group

LVEF

interventricular septal thickness

left ventricular lateral and anterior septal wall thickness

cardiac output

and +dp/dtmax decreased significantly 4 weeks after transplantation （P < 0.05）. Left ventricular end-diastolic pressure and –dp/dtmax did not change significantly before and after cell transplantation in both groups. Capillary density in BM-MNC group was greater than that in control group [（13.39 ± 6.96）/high power field vs. （3.50 ± 1.90）/high power field

P < 0.05]. Infarction area assessed by tetrazolium red staining and the infarction percentage decreased in BM-MNC group compared with those in control group （P < 0.05）. Conclusions Transplantation of BM-MNC into myocardium with ischemic reperfusion injury increases capillary density and decreases infarction area. It has significantly beneficial effect on cardiac systolic function rather than on diastolic function.