[Biological characteristics of human embryonic myoblasts in vitro]

This study was intended to observe the biological properties of primary human embryonic skeletal myoblasts cultured in vitro and to inquire about the possible differentiation mechanism. Isolated human embryonic myoblasts were identified by morphology and myosin immunohischemical staining. The proliferating myoblasts were shifted to DM (DMEM supplemented with 3% fetal bovine serum) to induce differentiation. The control group was cultured in GM (DMEM supplemented with 10% fetal bovine serum). The differentiation was tested by the rate of myotube formation (RMF); The change of cell cycle was tested by flow cytometry; the morphological features were observed by use of inverted microscope and TEM. The myogenic regulatory factors (MRFs) such as MyoD, Myogenin and Myf5 were assayed by RT-PCR. Results showed that the primary myoblasts cultured in DM, in comparison with those cultured in GM, had higher rate of myotube formation (RMF) and myofilament formation, and more of the myoblasts cultured in DM exited the S phase. The expression level of Myogenin mRNA was obviously higher than that of the control group, the increase of MyoD mRNA expression level was not so high, however, the expression of Myf5 mRNA was decreased. These data indicate that there is a possible mechanism between differentiation and cell cycle. Besides, the mRNA expression of myogenic regulatory factors (MRFs) occurs in different phase of differentiating myoblastes and implicates the diverse biological function.