Protective effects of exercise preconditioning on hindlimb unloading-induced atrophy of rat soleus muscle
Protective effects of exercise preconditioning on hindlimb unloading-induced atrophy of rat soleus muscle
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DOI：
10.1111/j.1748-1716.2009.01984.x
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发表时间：
2009-09-01
影响因子：
6.3
通讯作者：
Roy, R. R.
中科院分区：
文献类型：
--
作者：
Fujino, H.;Ishihara, A.;Roy, R. R.
目的：骨骼肌的激活和负荷水平的慢性下降与后肢卸载（HU）发生导致一些有害的变化。几种蛋白水解途径与肌原纤维蛋白降解增加有关。运动可以用来对抗蛋白质水解活性的增加，因此，可能能够防止一些与长期减少使用相关的有害变化。本研究的目的是确定单次预处理耐力运动在减弱2周HU对成年大鼠比目鱼肌质量、表型和力相关特性的影响方面的潜力。方法：雄性Wistar大鼠灌胃2周。一半的大鼠在2周HU之前立即进行了一次25分钟的跑步机运动。结果：HU大鼠比目鱼肌质量、最大破伤风张力、肌原纤维蛋白含量、抗疲劳性和I型（慢）肌球蛋白重链百分比均降低。此外，组织蛋白酶、钙蛋白酶、半胱天冬酶和atp -泛素-蛋白酶体蛋白水解途径的标记物增加。预适应耐力运动可减轻所有与HU相关的有害变化，并增加HSP72 mRNA表达和蛋白水平。结论：这些发现表明，运动预处理可能是对骨骼肌激活和负荷水平慢性降低的有害影响的有效对策，HSP72的升高可能是这些反应的相关机制之一。
Aim: A chronic decrease in the activation and loading levels of skeletal muscles as occurs with hindlimb unloading (HU) results in a number of detrimental changes. Several proteolytic pathways are involved with an increase in myofibrillar protein degradation associated with HU. Exercise can be used to counter this increase in proteolytic activity and, thus, may be able to protect against some of the detrimental changes associated with chronic decreased use. The purpose of the present study was to determine the potential of a single bout of preconditioning endurance exercise in attenuating the effects of 2 weeks of HU on the mass, phenotype and force-related properties of the soleus muscle in adult rats.Methods: Male Wistar rats were subjected to HU for 2 weeks. One half of the rats performed a single bout of treadmill exercise for 25 min immediately prior to the 2 weeks of HU.Results: Soleus mass, maximum tetanic tension, myofibrillar protein content, fatigue resistance and percentage of type I (slow) myosin heavy chain were decreased in HU rats. In addition, markers for the cathepsin, calpain, caspase and ATP-ubiquitin-proteasome proteolytic pathways were increased. The preconditioning endurance exercise bout attenuated all of the detrimental changes associated with HU, and increased HSP72 mRNA expression and protein levels.Conclusion: These findings indicate that exercise preconditioning may be an effective countermeasure to the detrimental effects of chronic decreases in activation and loading levels on skeletal muscles and that an elevation in HSP72 may be one of the mechanisms associated with these responses.