Development of exercise prescription for the prevention of chronic pain onset associated with hindlimb immobilization

本研究的目的是开发一种有效的治疗慢性疼痛的方法。为了实现这一目标，我们进行了一系列的实验，以确认预防性运动是否对慢性疼痛有效。我们让一组大鼠在跑步轮上自愿运动2周，而另一组不做运动。然后制作慢性铸造后疼痛（CPCP）模型，进行行为学和免疫组化检查。我们发现，CPCP诱导前运动的大鼠慢性机械性痛觉过敏比未运动的大鼠明显减少。此外，由于离同侧部位最远的尾部的机械性痛觉过敏减少，尾骨索的小胶质细胞的激活发生衰减。这些结果表明，在慢性疼痛发作前进行的运动可能会预防与后肢固定相关的慢性疼痛的发作。

The aim of the present study was the development of an effective therapy of chronic pain. In order to achieve it, we performed a series of experiments to confirm whether the preventive exercise is effective against the chronic pain. We let a group of rats exercise voluntary for 2 weeks using running wheel, while the other group did not do the exercise. Then we made chronic post-cast pain (CPCP) model and performed behavioral and immunohistochemical examination. We found that the chronic mechanical hyperalgesia in rats that exercised before CPCP was induced was more decrease compared with the rats that did not do the pre-exercise. Moreover, as the mechanical hyperalgesia of the tail farthest from the ipsilateral site is reduced, there occurs attenuation of the activation of microglia in the coccygeal cord. Those results suggested the possibility that the exercise performed before the onset of chronic pain may prevent the onset of chronic pain associated with hindlimb immobilization.