BMP-2 combined with salvianolic acid B promotes cardiomyocyte differentiation of rat bone marrow mesenchymal stem cells.

The present study tested the hypotheses that bone morphogenetic protein 2(BMP-2) combined with salvianolic acid B(Sal-B) enhance the differentiation of rat bone marrow mesenchymal stem cells (BMSCs) towards cardiomyocytes in vitro. BMSCs were treated with BMP-2 and Sal-B, alone or in combination, for 72 h, then added new media (excluding inductive substance) and cultured for 4 weeks. The morphologic characteristics, surface antigens and mRNA expression of several transcription factors were also assessed. We found that they could all be identified by the positive staining for cardiomyocyte-specific proteins, desmin and cardiac troponin T, in these cells. Furthermore, the mRNA expression of GATA-4 and Nkx2.5 genes was slightly increased on day 7, enhanced on day 14 and decreased on day 28 while α-MHC gene was not expressed on day 7, but expressed slightly on day 14 and enhanced on day 28. The expression of these cardiac-specific markers in treatment groups were all significantly higher than those in the control group, respectively (P < 0.05). Transmission electron microscopy showed that BMSCs in treatment groups all had myofilaments, z line-like substances and mitochondria. Taken together, these results indicate that BMP-2 combined with Sal-B promotes myocardial differentiation of BMSCs, which may represent a potential therapeutic strategy for the treatment of ischemic heart disease.