OBJECTIVEHuman umbilical cord blood contains abundant immature stem/progenitor cells, which may contribute to the repair of infarcted myocardium. Present study aimed to explore the feasibility and effects of human umbilical cord blood mononuclear cells (HUCBC) transplantation for the treatment of myocardial infarction.

METHODSForty-five male Wistar rats were randomly divided into three groups: (1) Myocardial infarction (MI plus vehicle, n = 15), (2) MI plus cell transplantation (HUCBC were implanted into the peri-infarct area immediately after MI, n = 15), (3) Normal control group (n = 15). After echocardiography and hemodynamic measurements, the rats were sacrificed for histological and immunochemical examinations one month post MI.

RESULTSThe transplanted HUCBC survived and participated the repair process in host heart. Significantly improved left ventricular function was evidenced by echocardiography in cell transplantation group compared to the MI control group. Left ventricular end-diastolic pressure was significantly reduced LVEDP (21.08 +/- 8.10) vs (30.82 +/- 9.59) mm Hg, P < 0.05], +dp/dt(max) [(4.29 +/- 1.27) vs (3.24 +/- 0.75) mm Hg/ms, P < 0.05] and -dp/dt(max) increased [(3.71 +/- 0.79) vs (3.00 +/- 0.49) mm Hg/ms, P < 0.05] in cell transplantation rats compared with MI control rats. vWF immunostaining examination showed significantly increased microvessels within the boundary of infarcted myocardium in cell transplantation group compared to the MI control group (P < 0.01).

CONCLUSIONSHUCBC transplantation may improve cardiac function in MI rats by promoting microvessel formation.