Bischoff R
Department of Anatomy and Neurobiology, Washington Univeristy School of Medicine, Saint Louis, Missouri 63110.
J Cell Biol. 1990 Jul;111(1):201-7. doi: 10.1083/jcb.111.1.201.
Satellite cells of adult muscle are quiescent myogenic stem cells that can be induced to enter the cell cycle by an extract of crushed muscle (Bischoff, R. 1986. Dev. Biol. 115:140-147). Here, evidence is presented that the extract acts transiently to commit cells to enter the cell cycle. Satellite cells associated with both live and killed rat myofibers in culture were briefly exposed to muscle extract and the increase in cell number was determined at 48 h in vitro, before the onset of fusion. An 8-12-h exposure to extract with killed, but not live, myofibers was sufficient to produce maximum proliferation of satellite cells. Continuous exposure for over 40 h was needed to sustain proliferation of satellite cells on live myofibers. The role of serum factors was also studied. Neither serum nor muscle extract alone was able to induce proliferation of satellite cells. In the presence of muscle extract, however, satellite cell proliferation was directly proportional to the concentration of serum in the medium. These results suggest that mitogens released from crushed muscle produce long-lasting effects that commit quiescent satellite cells to divide, whereas serum factors are needed to maintain progression through the cell cycle. Contact with a viable myofiber modulates the response of satellite cells to growth factors.
成年肌肉的卫星细胞是静止的肌源性干细胞，可被破碎肌肉的提取物诱导进入细胞周期（比肖夫，R. 1986年。《发育生物学》115:140 - 147）。在此，有证据表明该提取物短暂作用以使细胞进入细胞周期。将培养物中与活的和死亡的大鼠肌纤维相关的卫星细胞短暂暴露于肌肉提取物中，并在融合开始前的体外48小时测定细胞数量的增加。暴露于死亡而非活的肌纤维的提取物8 - 12小时足以使卫星细胞产生最大增殖。在活的肌纤维上维持卫星细胞增殖需要持续暴露超过40小时。还研究了血清因子的作用。单独的血清或肌肉提取物都不能诱导卫星细胞增殖。然而，在肌肉提取物存在的情况下，卫星细胞增殖与培养基中血清的浓度直接相关。这些结果表明，从破碎肌肉中释放的有丝分裂原产生持久的作用，使静止的卫星细胞进行分裂，而血清因子则是维持细胞周期进程所必需的。与活的肌纤维接触会调节卫星细胞对生长因子的反应。
