Histochemical responses of human soleus muscle fibers to long-term bedrest with or without countermeasures

被引:35
作者
Ohira, Y [1 ]
Yoshinaga, T
Nonaka, I
Ohara, M
Yoshioka, T
Yamashita-Goto, K
Izumi, R
Yasukawa, K
Sekiguchi, C
Shenkman, BS
Kozlovskaya, IB
机构
[1] Natl Inst Fitness & Sports, Dept Physiol & Biomech, Kanoya 8912393, Japan
[2] Natl Inst Fitness & Sports, Res Ctr Sports Training & Educ, Kanoya 8912393, Japan
[3] Natl Ctr Neurol & Psychiat, Tokyo 1878551, Japan
[4] St Marianna Univ, Sch Med, Dept Physiol 2, Kawasaki, Kanagawa 2168511, Japan
[5] Japan Space Utilizat Promot Ctr, Shinjuku Ku, Tokyo 1690051, Japan
[6] Natl Space Dev Agcy Japan, Tsukuba, Ibaraki 3058505, Japan
[7] Minist Publ Hlth Russia, Inst Biomed Problems, Dept Neurophysiol, Moscow, Russia
关键词
human soleus; fiber size; phenotype; bedrest; countermeasure;
D O I
10.2170/jjphysiol.50.41
中图分类号
Q4 [生理学];
学科分类号
071003 ;
摘要
Effects of 2- or 4-month bedrest in -6 degrees head-down tilt position with or without countermeasures on the histochemical properties of fiber phenotype and cross-sectional area (CSA) were studied in human soleus, The CSAs in slow fibers decreased similar to 32% during 4-month bedrest, This reduction was normalized after 4-month recovery. Although the reduction of percent slow fibers was not significant statistically, the percent intermediate fibers was significantly elevated 4 months after bedrest, Such shift in fiber type was not normalized following 1-month recovery. Effects of wearing an anti-g Penguin suit which has a modest, but continuous resistance at the knee and ankle (Penguin-1) or with knee resistance without loading on the ankle (Penguin-2) for 10 consecutive hours daily were also investigated during similar to 2 months of bedrest, The subjects performed knee extension and flexion for the last 15 min of each hour while in a supine position in bed. Bedrest-induced fiber atrophy was prevented in the Penguin-1 group but not the Penguin-2 group. Transformation of fiber type was not prevented in either Penguin suit group. It is suggested that long-term bedrest causes an atrophy and a shift of fiber phenotype toward fast-twitch type in human soleus, Data also indicated that loading on the muscle is an effective countermeasure for prevention of fiber atrophy but not fiber-type transformation.
引用
收藏
页码:41 / 47
页数:7
相关论文
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