Differentiation of myoblasts is accelerated in culture in a magnetic field

We developed a new cell stimulation method in which magnetic microparticles (MPs) were introduced into the cytoplasm of cultured myoblasts and the cel ls were cultured in a magnetic field. The differentiation of myoblasts was examined from the viewpoint of their morphology and myogenin production. Af ter exposure to the magnetic field, the cells containing MPs became larger and were elongated along the axis of the magnetic poles. Myogenin, a muscle -specific regulatory factor involved in controlling myogenesis, was formed earlier, and myotubes were seen earlier and more frequently in this group o f myoblasts than in the other groups (cells alone without magnetic field, c ells containing MPs but without magnetic field, and cells alone with magnet ic field). Moreover, we succeeded in differentiation of early muscle cells with striated myofibrils in culture at 0.05 T. The precisely quantitative a nd stable stimulus induced by a magnetic field developed in the present stu dy offers a new approach to elucidate the entire process of myoblast differ entiation into myotubes.