1993 Fiscal Year Final Research Report Summary
Searching for effective countermeasures to disuse muscle atrophy
| Project/Area Number |
04680131
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
体育学
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| Research Institution | The University of Tokushima |
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Principal Investigator |
MATOBA Hideki Faculty of Integrated arts and Sciences, The University of Tokushima, Professor, 総合科学部, 教授 (20035166)
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| Co-Investigator(Kenkyū-buntansha) |
MORITA Shunsuke Department of Liberal Arts, Yamaguchi University, Associate Professor, 教養部, 助教授 (30035159)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Tail suspension / muscle atrophy / rat soleus muscle / muscle tension / muscle protein / myosin heavy chain |
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| Research Abstract |
Using tail-suspension model, we investigated the mechanism of muscle atrophy in the rat. We also evaluated the effectiveness of periodic body weight bearing interspersed during tail-suspension as a countermeasure to muscle atrophy. Six-week-old rats were divided into 4 groups ; Suspension, Suspension interspersed with 12hour of weight bearing per day(S with 12 hr WB), Suspension interspersed with 1 hour of weight bearing per day(S with 1 hr WB), Control. Suspension lasted for 2 weeks. At the end of suspension period, the extensor digitorum longus(EDL)and soleus muscles from the 4 groups were removed and subjected to physiological and biochemical analyzes.
The results obtained in this study were as follows. Overall effects were much more profound on the soleus than on the EDL muscle. The suspension caused reduction in tetanic tension of the soleus muscle as judged either from absolute tension(g) or from tension per wet weight(g/mg). This reduction was not entirely attributable to a decrease in myofibrillar protein content or concentration. It was suggested that other factors than myofibrillar protein were also involved in the reduction in tetanic tension in the soleus muscle. The suspension made contraction of the soleus muscle faster. This was accompanied by the change in myosin heavy chain(HC) isozyme composition. A novel expression of myosin HC 2d and 2b were observed in addition to increased percentage expression of HC 2a and decreased percentage expression of HC 1. The body weight bearing for 1 hour per day partially suppressed suspension-induced changes. Prolongation of the time of the body weight bearing to 12 hours per day was shown to be a more effective as the countermeasure.
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