Pullman W E, Yeoh G C
J Cell Physiol. 1978 Aug;96(2):245-51. doi: 10.1002/jcp.1040960213.
It is well established that during muscle regeneration, the satellite cells which are in a state of mitotic arrest, can initiate cell division to produce myoblasts which subsequently fuse to form myotubes. However, whether myonuclei, contained within damaged myotubes, or "freed" as a result of the trauma, play any role in muscle regeneration remains unresolved. In myogenic cultures, it is possible to obtain renewed myogenesis when initial cultures are sub-cultured. The aim of this study, was to obtain evidence of the participation by myonuclei of primary cultures in myogenesis which occurs subsequently in secondary cultures. In culture, myonuclei can be labelled with H3-thymidine and their ultimate fate, either as "free" myonuclei or myonuclei associated with disrupted myotubes can be followed unequivocally. Three types of experiments are performed: (i) Primary myogenic cultures containing only myotubes are subcultured. (ii) Primary myogenic cultures containing myotubes with labelled myonuclei are disrupted and subcultured. (iii) Primary myogenic cultures containing myotubes with unlabelled myonuclei are mixed with labelled mononucleated myogenic cells and sub-cultured. In all instances no evidence of myogenesis from myonuclei is obtained. It is concluded that myonuclei, which were rendered postmitotic during myogenesis, remain so when muscle is disrupted and cannot re-enter the mitotic cycle.
众所周知，在肌肉再生过程中，处于有丝分裂停滞状态的卫星细胞可启动细胞分裂以产生成肌细胞，这些成肌细胞随后融合形成肌管。然而，受损肌管内所含的肌核，或因创伤而“释放”的肌核，在肌肉再生中是否发挥任何作用仍未得到解决。在成肌培养中，当初代培养物进行传代培养时，有可能获得新的成肌过程。本研究的目的是获得证据，证明初代培养物中的肌核参与随后在二代培养物中发生的成肌过程。在培养中，肌核可用H3-胸腺嘧啶核苷进行标记，并且它们的最终命运，无论是作为“游离”肌核还是与破裂肌管相关的肌核，都可以明确追踪。进行了三种类型的实验：（i）仅含有肌管的初代成肌培养物进行传代培养。（ii）含有带有标记肌核的肌管的初代成肌培养物被破坏并传代培养。（iii）含有带有未标记肌核的肌管的初代成肌培养物与标记的单核成肌细胞混合并传代培养。在所有情况下，均未获得肌核成肌的证据。得出的结论是，在成肌过程中进入有丝分裂后期的肌核，在肌肉受到破坏时仍保持这种状态，无法重新进入有丝分裂周期。
