ABSTRACT
<p><b>OBJECTIVE</b>To investigate whether cardiac tissue extracts from rats could mimic the cardiac microenvironment and act as a natural inducer in promoting the differentiation of bone marrow stromal cells (BMSCs) into cardiomyocytes.</p><p><b>METHODS</b>Three kinds of tissue extract or cell lysate [infarcted myocardial tissue extract (IMTE), normal myocardial tissue extract (NMTE) and cultured neonatal myocardial lysate (NML)] were employed to induce BMSCs into cardiomyocyte-like cells. The cells were harvested at each time point for reverse transcription-polymerase chain reaction (RT-PCR) detection, immunocytochemical analysis, and transmission electron microscopy.</p><p><b>RESULTS</b>After a 7-day induction, BMSCs were enlarged and polygonal in morphology. Myofilaments, striated sarcomeres, Z-lines, and more mitochondia were observed under transmission electron microscope. Elevated expression levels of cardiac-specific genes and proteins were also confirmed by RT-PCR and immunocytochemistry. Moreover, IMTE showed a greater capacity of differentiating BMSCs into cardiomyocyte-like cells.</p><p><b>CONCLUSIONS</b>Cardiac tissue extracts, especially IMTE, can effectively differentiate BMSCs into cardiomyocyte-like cells.</p>