反复牵伸收缩对雌性大鼠骨骼肌适应性的影响。
Effects of repeated lengthening contractions on skeletal muscle adaptations in female rats.
机构信息
Department of Physiology and Pharmacology, Robert C. Byrd Health Sciences Center, School of Medicine, West Virginia University, Morgantown, WV 26506-9229, USA.
出版信息
J Physiol Sci. 2010 Mar;60(2):143-50. doi: 10.1007/s12576-009-0078-y. Epub 2010 Jan 7.
We examined the adaptation of plantar flexor muscles of female rats to 6 weeks (5 days/week) of lengthening contractions. After repeated lengthening contractions, a decrease in myofiber area of gastrocnemius medialis (26%) was accompanied by an increase in extracellular matrix (ECM) (42%) and collagen content (30.9%) without changes in muscle mass. Decrease in myofiber area (13%) and muscle mass of soleus (19%) was associated with increased collagen content (28%) and ECM (15%). Relative number of soleus myofibers stained for fast myosin increased by 26%. For plantaris, increases in collagen content (32.3%), percent ECM (17%), and myofiber area (6%) were recorded. We also observed (1) increases (3.3%) in the collagen content of the Achilles tendon, (2) no change in the crosslink content of any of the tissues tested, and (3) no difference in the force-frequency relationship of the plantar flexor muscles. Substantial decreases in myofiber areas with increases in muscle connective tissue by 6 weeks of repeated lengthening contractions did not appear to result in isometric force loss.
我们研究了雌性大鼠跖屈肌对 6 周（每周 5 天）牵伸收缩的适应情况。经过反复的牵伸收缩，腓肠肌内侧肌纤维面积减少了 26%，而细胞外基质（ECM）增加了 42%，胶原含量增加了 30.9%，但肌肉质量没有变化。比目鱼肌的肌纤维面积减少了 13%，肌肉质量减少了 19%，同时胶原含量增加了 28%，细胞外基质增加了 15%。腓肠肌的快肌肌球蛋白染色的肌纤维数量增加了 26%。对于跖肌，胶原含量增加了 32.3%，细胞外基质百分比增加了 17%，肌纤维面积增加了 6%。我们还观察到（1）跟腱胶原含量增加了 3.3%，（2）所有测试组织的交联含量没有变化，（3）跖屈肌的力频关系没有差异。经过 6 周的反复牵伸收缩，肌纤维面积大量减少，而肌肉结缔组织增加，似乎并没有导致等长肌力的丧失。
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