Stiffness and muscle function with age and reduced muscle use
Stiffness and muscle function with age and reduced muscle use
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DOI：
10.1002/jor.1100170317
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发表时间：
1999-05-01
影响因子：
2.8
通讯作者：
Salsich, G
中科院分区：
文献类型：
--
作者：
Brown, M;Fisher, JS;Salsich, G
在雄性Fischer-344和Brown Norway大鼠中评估了被动肌肉僵硬度随年龄和废用的变化。研究了三组大鼠：年轻（约7个月大）、老年（约33个月大）和经历了2周后肢减重的老年大鼠，这是一种肌肉使用减少的模型。检查了四个后肢肌肉：比目鱼肌（姿势性）、跖肌（运动性）、趾长伸肌（非姿势性）和腓骨长肌（非姿势性）。在整个可用的运动范围内（在获得最大可达到的收缩或强直张力之前的肌肉伸长量），对于每一块肌肉，超最大刺激引起峰值强直张力，从而允许创建长度-张力曲线。被动张力（肌肉长度每毫米变化时遇到的量）也记录在整个可用的运动范围内，并随年龄增长而不变，随后肢减重而不变或减少;肌肉僵硬度在两种条件下均保持不变。然而，被动张力占总张力的比例随着年龄的增长，特别是与后肢减重。随着年龄的增长，肌肉运动范围的显著丧失，导致长度-张力曲线的显著移位，仅在跖肌中发生。后肢减重导致研究的所有四块肌肉的肌肉范围明显减少，这表明剩余的肌肉力量被限制在一个非常小的范围内。在所有四块肌肉中观察到与年龄和后肢减重相关的肌肉质量和收缩张力峰值显著下降。
Changes in passive muscle stiffness with age and disuse were assessed in male Fischer-344 and Brown Norway rats. Three groups of rats were studied: young (approximately 7 months old), old (approximately 33 months old), and old that had undergone 2 weeks of hindlimb unweighting, a model of reduced muscle use. Four hindlimb muscles were examined: the soleus (postural), plantaris (locomotor), extensor digitorum longus (nonpostural), and peroneus longus (nonpostural). Supramaximal stimuli elicited peak tetanic tensions throughout the available range of motion (amount of muscle elongation before the maximal attainable contractile or tetanic tension is obtained) for each muscle, permitting the creation of length-tension curves. Passive tension (amount encountered at each millimeter of change in muscle length) was also recorded throughout the available range of motion and was unchanged with aging and unchanged or reduced with hindlimb unweighting; muscle stiffness remained unchanged under both conditions. Passive tension, however, accounted for a greater proportion of total tension with age and particularly with hindlimb unweighting. A significant loss in muscle range of motion, resulting in a leftward shift in the length-tension curve, occurred with aging in only the plantaris. Hindlimb unweighting resulted in a marked loss in muscle range for all four muscles studied, suggesting that the remaining muscle force was constrained to a very small are. Significant declines in muscle mass and peak contractile tension, associated with age and hindlimb unweighting, were observed for all four muscles.