Age-Related Susceptibility to Muscle Damage Following Mechanotherapy in Rats Recovering From Disuse Atrophy.
Age-Related Susceptibility to Muscle Damage Following Mechanotherapy in Rats Recovering From Disuse Atrophy.
复制标题
从废用性萎缩中恢复的大鼠在机械疗法后对肌肉损伤的年龄相关易感性。
DOI：
10.1093/gerona/glab186
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
Dupont-Versteegden,EstherE
中科院分区：
文献类型：
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作者：
Hettinger,ZacharyR;Hamagata,Kyoko;Confides,AmyL;Lawrence,MarcusM;Miller,BenjaminF;Butterfield,TimothyA;Dupont-Versteegden,EstherE
在废用性萎缩期后，无法完全恢复失去的肌肉质量，容易使老年人失去独立性和生活质量差。我们之前的研究表明，中等负荷（4.5 N）的机械疗法可以增强成年大鼠萎缩后的肌肉质量恢复，但对老年成年大鼠没有作用。我们提出，老年肌肉横向刚度升高会抑制对机械治疗的生长反应，并假设更高的负荷（7.6 N）将克服这种对机械刺激的抵抗。F344/BN成年和老年雄性大鼠后肢悬吊14天，然后在7.6 N的腓骨肌上（RE + M）或不（RE）机械治疗7天恢复。7.6 N负荷是由被动测量横向刚度和线性扩大从4.5 N没有差异蛋白质周转或意味着纤维横截面积之间的观察再保险和再保险+ M为年长的成年老鼠或成年老鼠在7.6 N .然而,有更多的小肌肉纤维在年长的成年人,而不是成年老鼠,解释为增加16倍的频率小纤维表达胚胎肌凝蛋白重链。仅在7.6 N时，老年成年大鼠的中心成核、卫星细胞丰度和肌营养不良蛋白- /层粘连蛋白+纤维增加，而4.5 N在两种年龄均未引起损伤。我们的结论是，在考虑机械治疗过程中使用的负荷时，年龄是一个重要的变量，年龄相关的横向刚度可能使老年人在废用性萎缩后的恢复期易发生损伤。
The inability to fully recover lost muscle mass following periods of disuse atrophy predisposes older adults to lost independence and poor quality of life. We have previously shown that mechanotherapy at a moderate load (4.5 N) enhances muscle mass recovery following atrophy in adult, but not older adult rats. We propose that elevated transverse stiffness in aged muscle inhibits the growth response to mechanotherapy and hypothesize that a higher load (7.6 N) will overcome this resistance to mechanical stimuli. F344/BN adult and older adult male rats underwent 14 days of hindlimb suspension, followed by 7 days of recovery with (RE + M) or without (RE) mechanotherapy at 7.6 N on gastrocnemius muscle. The 7.6 N load was determined by measuring transverse passive stiffness and linearly scaling up from 4.5 N. No differences in protein turnover or mean fiber cross-sectional area were observed between RE and RE + M for older adult rats or adult rats at 7.6 N. However, there was a higher number of small muscle fibers present in older adult, but not adult rats, which was explained by a 16-fold increase in the frequency of small fibers expressing embryonic myosin heavy chain. Elevated central nucleation, satellite cell abundance, and dystrophin−/laminin+fibers were present in older adult rats only following 7.6 N, while 4.5 N did not induce damage at either age. We conclude that age is an important variable when considering load used during mechanotherapy and age-related transverse stiffness may predispose older adults to damage during the recovery period following disuse atrophy.