Department of Physiology, School of Medicine, Showa University.
Faculty of Arts and Sciences at Fujiyoshida, Showa University.
Biomed Res. 2021;42(2):67-76. doi: 10.2220/biomedres.42.67.
In this study, we employed a rodent model for persistent allodynia and hyperalgesia to determine whether voluntary exercise could exert analgesic effects on these pain symptoms. Rats were subcutaneously injected with formalin into the plantar surface of the right hind paw to induce mechanical allodynia and hyperalgesia. We assessed the analgesic effects of a voluntary wheel running (VWR) using the von Frey test and investigated microglial proliferation in the dorsal horn of the spinal cord. We also determined the effect of formalin and VWR on the protein expression levels of brain-derived neurotrophic factor (BDNF), its receptor TrkB, and K-Cl cotransporter 2 (KCC2), which play a key role in inducing allodynia and hyperalgesia. Rats with access to the running wheels showed beneficial effects on persistent formalin-induced mechanical allodynia and hyperalgesia. The effects of VWR were elicited through the suppression of formalin-induced microglial proliferation, TrkB up-regulation, and KCC2 down-regulation in the spinal cord. BDNF, however, might not contribute to the beneficial effects of VWR. Our results show an analgesic effect of voluntary physical exercise in a rodent model with persistent pain, possibly through the regulation of microglial proliferation and TrkB and KCC2 expression in the spinal cord.
在这项研究中，我们使用了一种持续性痛觉过敏和痛觉过高的啮齿动物模型，以确定自愿运动是否对这些疼痛症状具有镇痛作用。将福尔马林皮下注射到右后爪足底表面以诱导机械性痛觉过敏和痛觉过高。我们使用 von Frey 测试评估了自愿轮跑（VWR）的镇痛效果，并研究了脊髓背角中小胶质细胞的增殖。我们还确定了福尔马林和 VWR 对脑源性神经营养因子（BDNF）、其受体 TrkB 和 K-Cl 共转运蛋白 2（KCC2）的蛋白表达水平的影响，这些蛋白在诱导痛觉过敏和痛觉过高方面发挥着关键作用。有机会使用跑步轮的大鼠对持续性福尔马林诱导的机械性痛觉过敏和痛觉过高具有有益的影响。VWR 的作用是通过抑制脊髓中小胶质细胞的增殖、TrkB 的上调和 KCC2 的下调来发挥的。然而，BDNF 可能不会促进 VWR 的有益作用。我们的结果表明，自愿性体育锻炼在持续性疼痛的啮齿动物模型中具有镇痛作用，可能是通过调节脊髓中小胶质细胞的增殖以及 TrkB 和 KCC2 的表达。
