Hikida Robert S
Ohio Musculoskeletal and Neurological Institute (OMNI), Department of Biomedical Sciences, Ohio University College of Osteopathic Medicine, Athens, OH 45701, USA.
Curr Aging Sci. 2011 Dec;4(3):279-97. doi: 10.2174/1874609811104030279.
Vertebrate skeletal muscle fibers have two traits that make them unique: the fibers are multinucleated and their nuclei are post-mitotic. The activity and mass of the muscles in the body make them susceptible to constant injury. When this occurs, myonuclei can be increased or replaced by the adult stem cells of muscle, satellite cells (SCs). These SCs are vital for normal growth, repair and regeneration. This review collates recent studies to determine the size of the nuclear domains and its change with activity. The relationship between the percent change in myonuclear number, cross-sectional area, and myonuclear domain indicates that the nucleus generally maintains a highly regulated domain size in spite of large variations in fiber size. The SC divides to add nuclei for growth and repair, and the SC identification and number are discussed. It is concluded that SC number does not reflect a change in regenerative ability by the muscle. However, the SC number increases with changes in muscular activity, and any reduced number of satellite cells in the elderly does not appear to reflect a decline in reparative or regenerative ability. The effects of aging on SC function are reviewed, and the significance of the SC's connective tissue environment is emphasized as being a major factor in the decrement of the SC's ability to repair and regenerate the aging muscle. Therefore growth factors and cytokines in the connective tissue around the SC are major influences in the decline of SC function with age.
纤维是多核的，并且其细胞核是有丝分裂后的。身体中肌肉的活动和质量使其容易受到持续损伤。当这种情况发生时，肌核可以增加或被肌肉的成体干细胞——卫星细胞（SCs）所取代。这些卫星细胞对于正常生长、修复和再生至关重要。本综述整理了近期研究以确定核域的大小及其随活动的变化。肌核数量、横截面积和肌核域的百分比变化之间的关系表明，尽管纤维大小存在很大差异，但细胞核通常保持高度调节的域大小。卫星细胞分裂以增加用于生长和修复的核，并讨论了卫星细胞的识别和数量。得出的结论是，卫星细胞数量并不反映肌肉再生能力的变化。然而，卫星细胞数量随肌肉活动的变化而增加，老年人中卫星细胞数量的任何减少似乎都不反映修复或再生能力的下降。综述了衰老对卫星细胞功能的影响，并强调卫星细胞结缔组织环境的重要性是卫星细胞修复和再生衰老肌肉能力下降的主要因素。因此，卫星细胞周围结缔组织中的生长因子和细胞因子是卫星细胞功能随年龄下降的主要影响因素。
