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Effect of endurance training on accumulation of age-associated mitochondrial DNA deletions in old rats.

耐力训练对老年大鼠年龄相关线粒体 DNA 缺失积累的影响。

基本信息

批准号：
10680015
负责人：
KUNO Shinya
金额：
$ 2.11万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

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 … More 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

有人提出，与年龄相关的能量产物肌肉代谢下降是由几个物种中线粒体 DNA (mtDNA) 缺失的积累造成的 (Linnane 等人，1989)。然而，在大鼠骨骼肌中尚未成功检测到与年龄相关的 mt DNA 缺失（Filser 等，1997）。众所周知，运动可以改善肌肉新陈代谢，并可能有助于防止 mtDNA 缺失随着年龄的增长而积累。据我们所知，迄今为止，人们对运动对 mtDNA 缺失积累的影响知之甚少。本研究的目的是检测大鼠骨骼肌中与年龄相关的mtDNA缺失，并探讨耐力训练是否会影响不同类型骨骼肌中随年龄增长的mtDNA缺失积累。在本研究中，我们使用了 45 只 Wistar 雄性大鼠（10 周：n=29、90 周：n=16）。幼龄大鼠分为三组（20 m/min 训练组、30 m/min 训练组和对照组），老年大鼠分为两组（20 m/min 训练组和对照组）。训练方案包括 60 分钟、每周 5 天、持续 10 周。 m的线粒体DNA。通过聚合酶链式反应 (PCR) 分析比目鱼肌 (SOL) 和跖肌 (PLA)。检查了与年龄相关的 4.8-kb 缺失（常见缺失）的存在以及每只大鼠检测到的缺失产物的数量。通过每组中大鼠的数量来评估常见缺失的存在，并通过对每只大鼠可视化的缺失产物进行计数来估计缺失的数量。 2只年轻大鼠（6.9%）和9只老年大鼠（56.3%）在SOL中存在共同缺失，而2只年轻大鼠（6.9%）和15只老年大鼠（93.8%）在PLA中存在共同缺失。在年轻组或老年组中都没有发现耐力训练对常见缺失的存在有影响。在旧组中，PLA 中常见缺失的出现率高于 SOL。 PLA 中的缺失数量随着年龄的增长而显着增加（p<0.01）。然而，SOL 缺失数量在年轻组和老年组之间没有显着差异。在任何组中均未观察到训练对缺失数量的影响。在年轻组中，SOL 中的 mtDNA 缺失产物数量高于 PLA 中。然而，在老年组中，SOL 中的值低于 PLA 中的值。总之，我们可以检测到大鼠骨骼肌中与年龄相关的 mtDNA 缺失的积累，并且在本研究中观察到耐力训练对此没有影响。此外，mtDNA 缺失的积累可能因纤维类型而异。较少的