1999 Fiscal Year Final Research Report Summary
Effect of endurance training on accumulation of age-associated mitochondrial DNA deletions in old rats.
| Project/Area Number |
10680015
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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 Field |
体育学
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| Research Institution | University of Tsukuba |
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Principal Investigator |
KUNO Shinya Institute of Health and Sport Sciences. University of Tsukuba Assistant Professor, 体育科学系, 講師 (70242021)
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| Co-Investigator(Kenkyū-buntansha) |
MIYAZAKI Rika Institute of Health and Sport Sciences. University of Tsukuba Research Associate, 体育科学系, 助手 (20292542)
HAYASHI Jun-ichi Institute of Biological Sciences. University of Tsukuba Associate Professor, 生物科学系, 助教授 (60142113)
KATSUTA Shigeru Institute of Health and Sport Sciences. University of Tsukuba Professor, 体育科学系, 教授 (70038446)
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| Project Period (FY) |
1998 – 1999
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| Keywords | aging / exercise / mitochondorial DNA |
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| Research Abstract |
It has been proposed that age-associate decline of muscle metabolism of energy product are resulted from the accumulation of mitochondrial DNA (mtDNA) deletions in several species (Linnane et al., 1989). However, age-associated mt DNA deletions have not been successfully detected in the rat skeletal muscles (Filser et al., 1997). Exercise has been known to improve the muscle metabolism and then may have a benefit to prevent the accumulation of mtDNA deletions with age. As long as we know, little has been known about the effects of exercise on the accumulation of mtDNA deletions so far. The purpose of this study was to detect the age-associated mtDNA deletions in the rat skeletal muscles, and to examine whether endurance training effects on the accumulation of mtDNA deletions with age in different type of skeletal muscle. We used forty five Wistar male rats (10 wks : n=29, 90 wks : n=16) in this study. Young rats were divided into three groups (20 m/min training group, 30 m/min training
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group and control group) and old rats were divided into two groups (20 m/min training group and control group). The training protocol consisted of 60 min, 5 days/wk for 10 wks. MtDNA of m. soleus (SOL) and m.plantaris (PLA) were analyzed by polymerase chain reaction (PCR). The presence of age-associated 4.8-kb deletion (common deletion) and the number of deletion products detected per rat were examined. The presence of common deletion was evaluated by the number of rats in each group and the number of deletion was estimated by counting the deletion products visualized per rat. Two of the young rats (6.9%) and nine of the old rats (56.3%) had common deletion in SOL, while two of the young rats (6.9%) and fifteen of the old rats (93.8%) had in PLA. No effect of the endurance training on the presence of common deletion was seen in either the young group or the old group. In the old group, the presence of common deletion was higher in PLA than that in SOL. The numbers of deletion in PLA increased with age significantly (p<0.01). However the numbers of deletion in SOL showed no significant difference between the young and the old groups. The training effect on the numbers of deletion was not observed in any groups. In the young group, the number of mtDNA deletion products in SOL was higher than that in PLA. In the old group, however, the value was lower in SOL than in PLA.
In conclusion, we could detect the accumulation of age-associated mtDNA deletions of the rat skeletal muscles, and observed no endurance training effect on that in this study. Moreover, the accumulation of mtDNA deletions can be specific according to fiber types. Less
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