Bone marrow stromal cells in rat can be induced to myocardial cells in vitro

Purpose. Adult marrow stromal cell(MSC) is a kind of multipotent progenitor cell, They can be greatly expanded in vitro and induced to differentiate into non-hematopoietic cell types. In this study, we found on the potential of MSC to differentiate into cardiomyocyte precursors by induction in vitro. Methods. Bone marrow cells were isolated from adult SD rat's leg bone, the MSC were purified by culture-expanded, and expanded as indifferentitated cells in culture for more than 8 passages. After treated with DNA demethylating agent 5-azacytidine for twice. The MSC differentiation was observed by phase-contrast microscope, flow cytometry (FACS), immunohistochemistry and RT-PCR. Results. After treated the MSC with 5-azacytidine for 10 days, the clones of adherent fibroblast-like cells were formed spindle-shaped, connected with adjoining cells, aligned in a striated pattern after 20 days and formed myotube-like structures about 1 month. The phenotype of induced MSC incline to uniform small cells type by FACS. After differentiation, MSC acquired many morphologic features of cardiac muscle, desmin positive cells were about 35% and cTnT positive cells nearly 10% by immunohistochemistry staining, they expressed several cardiac-special genes, including the GATA-4 transcription factor, atrial nateiuretic protein(ANP) and a-MHC genes. Conclusions. The marrow stromal cells can be differentiated to cardiomyocytes in vitro by profit inductive condition. They are ideal donor cells in cellular cardiomyoplasty to treat myocardial infarction.