Objective    To investigate the effects of grafted mesenchymal stem cells (MSCs) on cardiac function

myocardium structure and monophasic action potential (MAP) in rabbits with dilated cardiomyopathy (DCM).     Methods    Thirty eight rabbits were randomized into 3 groups: (1)normal group(n=12)

(2)DCM cell implantation group (n=13)

(3)DCM control group(n=13). Adriamycin was applied to create rabbit DCM model. Three weeks after the model was built

intramyocardial injection of MSCs was given to animal for cell transplatation  and the cultivation matrials  to the normal group. In 4 weeks later

  the echocardiography and MAP studies were performed to evaluate cardiac function and electrophysiology

histologic section of the implanted sites. The expression of cardiac Troponin T(cTnT) and connexin 43(Cx43)was investigated with immunohistochemistry.     Results    Compared with the normal group

the value for monophasic action potential amplitude (MAPA)and the maximun velocity in “0” phase (Vmax)decreased significantly in DCM rabbits

while the value for 50% monophasic action potential durations (MAPD50) and 90% monophasic action potential duration(MAPD90) increased significantly

  the effective refractory period (ERP) increased

too. However the increase of MAPD was less in cell impantation group than in DCM control group with no after -depolarization (two was found in the DCM control group).  Compared with DCM control group

structual abnormalities was less grave in the cell implantation group and the implanted MSCs could express cTnT and Cx43.     Conclusion    Implanted MSCs can improve heart function

abate the structural abnormalities and may inhibit the progression of electrophysiology derangement.