Expressions of myogenic markers in skeletal muscle differentiation of human bone marrow mesenchymal stem cells

Objective To investigate the expressions of myogenic markers MyoD,myogenin,and desmin in skeletal muscle differentiation of human bone marrow mesenchymal stem cells(hBM-MSCs).Methods Myogenic markers MyoD,myogenin,and desmin of hBM-MSCs cultured in vitro were detected by immunofluorescence and RT-PCR.A total of 21 8-to-10 week-old immunosuppressed mdx mice were transplanted with 1×107 passage 5 of hBM-MSCs.The mice were euthanized 2-24 weeks after transplantation,and gastrocnemius muscle were analyzed for human MyoD,myogenin,desmin,and dystrophin(Dys)expressions by immunohistochemistry and RT-PCR.Results The numbers of MyoD-,myogenin-,and desmin-positive cells per 100 hBM-MSCs were 23.5±5.3,30.7±6.2,and 28.4±5.7,respectively.MyoD,myogenin,and desmin mRNA was observed in passage 5 of hBM-MSCs.After two weeks of hBM-MSCs transplantation,a small number of MyoD-and myogenin-positive cells were observed in skeletal muscle of mdx mice,and desmin-positive cells were observed 4 weeks after transplantation.Expressions of MyoD and myogenin were detected in the muscle of mdx mice 2-4 weeks after hBM-MSCs transplantation,which reached a peak 12-16 weeks later.Desmin was expressed in the muscle of mdx mice 4-8 weeks after transplantation,with much more expression after 16 weeks of transplantation.A small number of Dys-positive cell and Dys mRNA expression were presented in the muscle of mdx mice 4 and 8 weeks after hBM-MSCs transplantation,respectively.The expression of Dys in the muscle of mdx mice increased gradually after transplantation.Conclusion hBM-MSCs have the potential of myogenic differentiation in vitro and contribute to myogenic conversion in xenogeneic animal,during which the up-regulation of MyoD and myogenin expressions may play an important role.