Zushi Kazumi, Yamazaki Toshiaki
Division of Health Sciences, Graduate School of Medical Science, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942, Japan ; Department of Rehabilitation, Minamigaoka Hospital.
Division of Health Sciences, Graduate School of Medical Science, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942, Japan.
J Jpn Phys Ther Assoc. 2012;15(1):1-8. doi: 10.1298/jjpta.Vol15_001.
The purpose of this study was to investigate the effect of reloading on atrophied muscle and the time course of hypertrophy and regeneration. Forty-nine male Wistar rats were randomly assigned to groups for hindlimb suspension (HS), hindlimb suspension and reloading (R), or control (C0). Rats in the HS group were suspended for 14 days. Rats in the R group were randomly divided into five subgroups for different post-hindlimb-suspension recovery times. Briefly, each subgroup was suspended for 14 days and given 1 day of reloading (R1), 3 days of reloading (R3), 7 days of reloading (R7), 10 days of reloading (R10), or 14 days of reloading (R14). Myonuclear numbers were significantly decreased in the groups with hindlimb suspension and 1 day and 3 days of reloading compared with that in the control group. We focused on the processes of change of mean myofiber cross-sectional area and myonuclear domain size; the degrees of increase of both indexes were limited until 3 days of reloading, and significantly increased after 7 days of reloading. An important finding of the current study was that the processes of muscle hypertrophy and regeneration did not show uniform change. In addition, there were differences in the ratio of increase among the stages of hypertrophy and regeneration. Therefore, consideration of the duration and method of physiotherapeutic intervention for atrophied muscle on the basis of the process of hypertrophy and regeneration is needed to provide more effective physiotherapy.
本研究的目的是调查再负荷对萎缩肌肉的影响以及肥大和再生的时间进程。49只雄性Wistar大鼠被随机分为后肢悬吊组（HS）、后肢悬吊及再负荷组（R）或对照组（C0）。HS组大鼠悬吊14天。R组大鼠随机分为五个亚组，分别给予不同的后肢悬吊后恢复时间。简而言之，每个亚组悬吊14天，然后分别给予1天再负荷（R1）、3天再负荷（R3）、7天再负荷（R7）、10天再负荷（R10）或14天再负荷（R14）。与对照组相比，后肢悬吊组以及再负荷1天和3天的组中肌核数量显著减少。我们重点关注平均肌纤维横截面积和肌核域大小的变化过程；在再负荷3天之前，这两个指标的增加程度有限，而再负荷7天后显著增加。本研究的一个重要发现是，肌肉肥大和再生过程并未呈现出一致的变化。此外，肥大和再生各阶段的增长比例也存在差异。因此，需要根据肥大和再生过程来考虑针对萎缩肌肉的物理治疗干预的持续时间和方法，以提供更有效的物理治疗。
