The specific force of single intact extensor digitorum longus and soleus mouse muscle fibers declines with aging
The specific force of single intact extensor digitorum longus and soleus mouse muscle fibers declines with aging
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DOI：
10.1007/s002320010025
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发表时间：
2000-12-01
影响因子：
2.4
通讯作者：
Delbono, O
中科院分区：
文献类型：
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作者：
González, E;Messi, ML;Delbono, O
在本研究中，我们首次测量了来自年轻成年（2-6）、中年（12-14）和老年（20-24月龄）小鼠的快速（指长伸肌，EDL）和慢抽动（比目鱼肌）的单个完整纤维产生的等长比力（SF，力标准化到横截面积）。SF也在年轻小鼠的单个完整的指屈肌短纤维中进行了测量。肌肉纤维根据收缩动力学分为快肌纤维和慢肌纤维。青壮年小鼠EDL和比目鱼肌纤维记录的最大SF无显著差异。从年轻的中年小鼠到老年小鼠，EDL和比目鱼肌纤维的最大SF呈明显的年龄依赖性下降。青年、中年和老年小鼠EDL纤维的SF分别为377 +/- 18、417 +/- 20和279 +/- 18 kPa，年龄匹配小鼠比目鱼肌纤维的SF分别为397 +/- 17、405 +/- 24和320 +/- 33 kPa。在中老年小鼠中，EDL和比目鱼肌纤维中引起最大力所需的频率没有显著差异。综上所述，快肌纤维和慢肌纤维单个完整肌纤维的比力随着年龄的增长而下降，慢肌纤维的比力下降更为明显。
In the present study we measured,for the first time, the isometric specific force (SF, force normalized to cross sectional area) generated by single intact fibers from fast- (extensor digitorum longus, EDL) and slow-twitch (soleus) muscles from young adult (2-6), middle-aged (12-14) and old (20-24 month-old) mice. SF has also been measured in single intact flexor digitorum brevis fibers from young mice. Muscle fibers have been classified into fast- or slow-twitch based on the contraction kinetics. Maximum SF recorded in EDL and soleus fibers from young and middle-aged mice did not differ significantly. A significant age-dependent decline in maximum SF was recorded in EDL and soleus fibers from younger middle-aged to old mice. The SF was 377 +/- 18,:417 +/- 20 and 279 +/- 18 kPa for EDL fibers from young, middle-aged and old mice, respectively and 397 +/- 17, 405 +/- 24 and 320 +/- 33 kPa for soleus fibers from age-matched mice, respectively. The frequency needed to elicit maximum force in EDL and soleus fibers from middle-aged to old mice did not differ significantly. In conclusion, the specific force developed by both fast and slow-twitch single intact muscle fibers declines with aging and more significantly in the former.