Mozdziak P E, Pulvermacher P M, Schultz E
Department of Anatomy, University of Wisconsin Medical School, Madison, Wisconsin 53706, USA.
J Appl Physiol (1985). 2000 Jan;88(1):158-64. doi: 10.1152/jappl.2000.88.1.158.
The role of satellite cells and DNA unit size in determining muscle size was examined by inhibiting postnatal skeletal muscle development by using hindlimb suspension. Satellite cell mitotic activity and DNA unit size were determined in the soleus muscles from hindlimb-suspended and age-matched weight-bearing rats before the initiation of hindlimb suspension, at the conclusion of a 28-day hindlimb-suspension period, 2 wk after reloading, and 9 wk after reloading. The body weights of hindlimb-suspended rats were significantly (P < 0.05) less than those of weight-bearing rats at the conclusion of hindlimb suspension, but they were the same (P > 0. 05) as those of weight-bearing rats 9 wk after reloading. The soleus muscle weight, soleus muscle weight-to-body weight ratio, myofiber diameter, nuclei per millimeter, and DNA unit size for the hindlimb-suspended rats were significantly (P < 0.05) smaller than for the weight-bearing rats at all recovery times. Satellite cell mitotic activity was significantly (P < 0.05) higher in the soleus muscles from hindlimb-suspended rats 2 wk after reloading, but it was the same (P > 0.05) as in weight-bearing rats 9 wk after reloading. Juvenile soleus muscles failed to achieve normal muscle size 9 wk after reloading because there was incomplete compensation for the hindlimb-suspension-induced interruptions in myonuclear accretion and DNA unit size expansion.
通过后肢悬吊抑制出生后骨骼肌发育，研究卫星细胞和DNA单位大小在决定肌肉大小中的作用。在开始后肢悬吊前、28天的后肢悬吊期结束时、重新负重2周后以及重新负重9周后，测定后肢悬吊大鼠和年龄匹配的负重大鼠比目鱼肌中的卫星细胞有丝分裂活性和DNA单位大小。后肢悬吊大鼠在悬吊期结束时体重显著低于负重大鼠（P<0.05），但在重新负重9周后与负重大鼠相同（P>0.05）。在所有恢复时间点，后肢悬吊大鼠的比目鱼肌重量、比目鱼肌重量与体重之比、肌纤维直径、每毫米细胞核数和DNA单位大小均显著小于负重大鼠（P<0.05）。重新负重2周后，后肢悬吊大鼠比目鱼肌中的卫星细胞有丝分裂活性显著高于负重大鼠（P<0.05），但在重新负重9周后与负重大鼠相同（P>0.05）。幼年比目鱼肌在重新负重9周后未能达到正常肌肉大小，因为对后肢悬吊引起的肌核增殖和DNA单位大小扩展中断的补偿不完全。
