Study On The Effect Of Mature Myocardial Cell To Induce The Early Embryo Or ESCs Differentisted Directly

Objective: To confirm the especial effect of mature myocardial cell to induce the early embryo or ESCs differentiated directly, to provide the theoretical basis about establishing a simple and applied technique of cellular transplanting of ESCs.Methods: Primary myocardial cell was isolated from Sprague-Dawley neonatal rats, and marked the cell nuclear with DAPI . The early embryo (8～16 cell stage) obtained from Kunming mouse through natural mating or superovulation respectively was used to cocultur with myocardial cell or correlated myocardial microenvironment; the first or the second generation of ESCs was obtained from the blastocyst (3.5～4 days ) through serial subcultivation, which was cocultured with myocardial cell and cardiac fibroblasts. Dynamic video was used to observe the cardiac differentiation of the early embryo or ESCs. Expression of cTnT andα-Actinin in the differentiated cells from the early embryo or ESCs were examined at 3 d,7 d,14 d by immunocytochemistry.Results: (1) The early embryo could grow and differentiate when cocultured with myocardial cell and cardiac fibroblasts. But the differentiated cells had no cTnT expressed. (2)The cell and/or the cell mass of the first or the second generation of ESCs could be induced to differentiate into beating cardiomyocyte when cocultured with myocardial cell on the 7th day, and beating with the frequency about 30～50/min on the 14th day. More than quarter of the cell mass of ESCs was observed with rhythmicity besting in the best experimental group. The rate of the cardiomyocyte differentiated from ESCs was not increased when associated with DMSO(6%). (3)ESCs could be induced to differentiate, with cTnT andα-Actinin expressed in 27 percent of the differentiated cells when cocultured with myocardial cell;No cTnT andα-Actinin expressed when cocultured with cardiac fibroblasts;CTnT andα-Actinin expressed in 3 percent of the differentiated cells when cocultured with DMSO (6%).No significant difference when cocultured with myocardial cell associated DMSO (6%).Conclusions: (1) Early embryo could grow and differentiate when cocultured with myocardial cell and cardiac fibroblasts, but no cardiomyocyte with cTnT expressed in the differentiated cells. Direct cell-to-cell contact was blocked while the trophoblastic cell differentiated, which mignt influence ESCs to differentiate into cardiomyocytes. (2) ESCs which not be established into the cell system could be induced to differentiate into beating cardiomyocyte. ESCs might be induced to differentiate into cardiomyocytes when cocultured with myocardial cell. And it could be at a high rate of differentiation than the natural differentiated group. It's mean that mature myocardial cell might be the important factor on directly inducing.