| Co-Investigator(Kenkyū-buntansha) |
YOSHIDA Akira Kagoshima University, Graduate School of Medical and Dental Sciences, Research Associate, 大学院医歯学総合研究科, 助手 (40347109)
KAWAHIRA Kazumi Kagoshima University, Graduate School of Medical and Dental Sciences, Professor, 大学院医歯学総合研究科, 教授 (20117493)
OOWATASHI Akihiko Kagoshima University, Faculty of Medicine, Research Associate, 医学部, 助手 (30295282)
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| Budget Amount *help |
¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 2006: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 2005: ¥3,400,000 (Direct Cost: ¥3,400,000)
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| Research Abstract |
Background : Passive stretch is one of stimulating factors for muscle growth. To have the effect at one time, we cannot help stretching muscles for over few hours. However, it is hard to make time to give stretching muscles for a few hours clinically.
Objectives : To evaluate the effect of passive stretch, applied for a short time in several days to the medial gastroeunemius muscles, on MyoD, myogenin, and myosin heavy chain (MHC) gene expressions.
Methods : Twenty-eight 7-week-old male Wister rats were used. They were divided into three groups. In the first group, eleven rats were stretched right medial gastrocunemius muscles repetitively 15 times in one minute during 15 minutes, four every other days. In second group, the same number rats were stretched continuously for 15 minutes, four every other days. In the two groups, contralateral muscles were without stretch as the control side. The third group, they were not stretched both side as control goup. Twenty four hour after the last session of stretch, muscles were removed and messenger of ribonucleic acid (mRNA) of them were extracted. The mRNA levels of MyoD, myogenin, MHC were assessed by real-time polymerase chain reaction.
Results : MyoD, myogenin and MHC mRNA levels increased compared with control sides, in repetitive stretch muscles and continuous stretch muscles. No difference was found in the mRNA of MyoD and myogenin gene expression after repetitive stretch group and continuous stretch group compared with control group. The MHC mRNA increased in both groups compared with control side. Furthermore there was a significant difference between repetitive stretch and control, but no significant difference between continuous stretch and control group.
Conclusions : MyoD, myogenin, and MHC gene expression were increased by passive stretch for 15 minutes for several days. This effect is especially clear in repetitive stretch compared to continuous stretching.
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