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EFFECTS OF MESENCHYMAL STEM CELL TRANSPLANTATION ON CARDIAC FUNCTION, STRUCTURE, AND ELECTROPHYSIOLOGY IN RABBITS WITH DILATED CARDIOMYOPATHY

OBJECTIVE: The objective of this study was to explore the influence of implanted mesenchymal stem cells (MSCs) on cardiac function, structure, and electrophysiology in rabbits with dilated cardiomyopathy (DCM). METHODS: Thirty-eight rabbits were randomly assigned to 3 groups: (1) normal rabbits (n = 12); (2) rabbits with DCM cell implantation (n = 13); or (3) DCM control rabbits (n = 13). Adriamycin was applied to create the rabbit DCM model. Rabbits for cell transplantation received an intramyocardial injection of MSCs. Four weeks later, heart function morphology and electrophysiology changes were observed. The expression of cardiac Troponin T and connexin 43 was investigated through immunohistochemistry. RESULTS: Compared with normal rabbits, the cardiac function of DCM rabbits was impaired, but this impaired function was improved by MSC implantation. The value for monophasic action potential amplitude and the maximum velocity in ¡°0¡±phase decreased significantly in DCM rabbits, whereas the value for 50% monophasic action potential durations (MAPD) and 90% MAPD were increased significantly. The effective refractory period increased also. The comparison of both DCM groups showed that the prolongation of MAPD was shorter in the cell implantation group than in the DCM control group, and no after-depolarization was observed, whereas early after-depolarization was recorded in 2 rabbits in the DCM control group. Histology analysis showed that the structural abnormalities in the cell implantation group were less than those in the DCM control group, and the implanted MSCs could express cardiac Troponin T and connexin 43. CONCLUSIONS: Implanted MSCs can improve heart function, reduce the structural abnormalities, and possibly inhibit the progression of electrophysiologic derangement.