Essential role of satellite cells in the growth of rat soleus muscle fibers
Essential role of satellite cells in the growth of rat soleus muscle fibers
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DOI：
10.1152/ajpcell.00497.2007
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发表时间：
2008-08-01
影响因子：
5.5
通讯作者：
Ohira, Yoshinobu
中科院分区：
文献类型：
--
作者：
Kawano, Fuminori;Takeno, Yoshiaki;Ohira, Yoshinobu
本文研究了重力负荷和重力卸载对大鼠比目鱼肌纤维横截面积和长度以及总纤维数增长的影响。此外，卫星细胞和肌核在这些特性的生长中的作用也进行了研究。对出生后第4天至第3个月的新生大鼠进行尾部悬吊的后肢去负荷，有或没有3个月的再负荷。在整个肌肉和/或从肌腱到肌腱取样的单纤维中测量形态学特性。生长相关的增加比目鱼肌重量和纤维横截面积在卸载组分别为68%和69%，低于年龄匹配的控制。而纤维数量和长度的增加不受卸载的影响。生长相关的静止卫星细胞和肌细胞核的数量的增加被抑制卸载。与生长相关的有丝分裂活跃的卫星细胞的减少，即使在对照组中也可见（20%，P > 0.05），也被刺激（80%）。在3个月的卸载过程中，肌核的增加仅为40倍，而对照组为92倍。抑制心肌细胞数量的增加与细胞凋亡无关。与对照组相比，未加载组的肌钙蛋白结构域的大小较小，单个核的大小较大，但随着生长而减少。然而，所有这些参数，抑制卸载，增加对控制水平一般通过重新加载。这表明，卫星细胞相关的刺激，在响应重力负荷比目鱼肌纤维的横截面生长中起着至关重要的作用。
Effects of gravitational loading or unloading on the growth-associated increase in the cross-sectional area and length of fibers, as well as the total fiber number, in soleus muscle were studied in rats. Furthermore, the roles of satellite cells and myonuclei in growth of these properties were also investigated. The hindlimb unloading by tail suspension was performed in newborn rats from postnatal day 4 to month 3 with or without 3-mo reloading. The morphological properties were measured in whole muscle and/or single fibers sampled from tendon to tendon. Growth-associated increases of soleus weight and fiber cross-sectional area in the unloaded group were similar to 68% and 69% less than the age-matched controls. However, the increases of number and length of fibers were not influenced by unloading. Growth-related increases of the number of quiescent satellite cells and myonuclei were inhibited by unloading. And the growth-related decrease of mitotically active satellite cells, seen even in controls (20%, P > 0.05), was also stimulated (80%). The increase of myonuclei during 3-mo unloading was only 40 times vs. 92 times in controls. Inhibited increase of myonuclear number was not related to apoptosis. The size of myonuclear domain in the unloaded group was less and that of single nuclei, which was decreased by growth, was larger than controls. However, all of these parameters, inhibited by unloading, were increased toward the control levels generally by reloading. It is suggested that the satellite cell-related stimulation in response to gravitational loading plays an essential role in the cross-sectional growth of soleus muscle fibers.