2001 Fiscal Year Final Research Report Summary
Mitochondrial DNA Damage and Morphological Change in Disuse Atrophied Skeletal Muscles and Effect of Therapeutic Exercise
| Project/Area Number |
11835029
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Institution | IBARAKI PREFECTURAL UNIVERSITY OF HEALTH SCIENCES |
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Principal Investigator |
SAKAI Yasutomo IBARAKI PREFECTURAL UNIVERSITY OF HEALTH SCIENCES, DEPARTMENT OF HEALTH SCIENCES, TEACHING ASSISTANT & RESEARCHER, 保健医療学部, 助手 (80274984)
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| Project Period (FY) |
1999 – 2001
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| Keywords | Hind-limb Suspension / Disuse Atrophy / Mitochondrial DNA (mtDNA) / Soleus Muscle / Rat / Therapeutic Exercise / Ultrastructure / Muscle Stretching |
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| Research Abstract |
1) Mitochondrial DNA damage and morphological change in disuse atrophy :
In this research project we studied mitochondrial DNA (mtDNA) deletion of cells and microstructural changes from the rat soleus muscle subjected to disuse atrophy by hind-limb suspension for two or four weeks. No such deletions were detected in the mtDNA from two weeks of free weight-bearing after two weeks of hind-limb suspension. After two weeks of disuse atrophy, many mitochondrial structures in the muscle were miniaturized and other structures became blurred. And also molten thin actin filaments were found on the periphery of the Z-disk. After four weeks of disuse, alignment of the fibrils became ragged the Z-disks were deteriorated.
2) Stretching and disuse atrophy of skeletal muscle :
In this project we investigated the extent of atrophic change and recovery from skeletal muscle subjected to hind-limb suspension for two weeks with the soleus in an elongated position. Whereas disuse atrophy muscles without stret
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ching decreased in wet-weight and in total RNA, based on inhibition of gene expression and genetic transcription in the protein metabolism, preliminary results suggested that muscle stretching may induce inhibitory action of muscle atrophy.
3) Effect of therapeutic exercise on disuse atrophied skeletal muscles :
Both acute overload exercise and disuse atrophy have induced mtDNA deletion with muscle ultra-structural damage in this research project. Nevertheless, endurance exercise and muscle stretching appear to provide effective means to inhibit muscle atrophy, so then this project will focus on the potential importance of these methods in therapeutic exercise.
4) Conclusion :
Disuse atrophy leads to oxidative stress, damage of muscle tissue and mutation of mtDNA. The association of damage due to disuse atrophy with oxidative stress may have clinical implications in determining what form of therapeutic exercise in beneficial in preventing or suppressing such damage. We will be pursuing this question. Less
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