[Study of inducing differentiation of bone marrow mesenchymal stem cells of rat into cardiac myocytes in vitro].

ABSTRACT

OBJECTIVE: To investigate the role of cardiac myocytes in the differentiation of bone marrow mesenchymal stem cells (MSCs) to cardiac myocytes and the biological properties in the course. METHODS: The bone marrow of the extremities of the rats was flushed, and bone marrow MSCs were obtained by method of density gradient centrifugation. They were cultured. The second passage of cultured MSCs were labelled with bromodeoxyuridine (BrdU). The cardiac myocytes were obtained from the apex of rat heart with trypsin digestion method, and they were cocultured with labeled MSCs. The developmental changes of bone marrow MSCs were observed under light microscope with immunohistochemical staining for BrdU and alpha-sarcomeric actin on the 3rd day, and electron microscopic examination on the 5th day. RESULTS: MSCs proliferated fast in primary culture and subculture, positive rate was (90.34+/-2.31)%, and there was statistical difference when it compared with control group [(4.07+/-1.35)%, P<0.01]. The morphology of MSCs changed significantly after coculture. There were new cells nuclei of which were positively stained for BrdU and its cytoplasm positive for actin. Under transmissive electron microscope, sarcomeres like structure and abnormal Z line were observed in cytoplasm. CONCLUSION: Cardiac myocytes can effectively induce bone marrow MSCs to differentiate into cardiac myocytes by coculturing.