Department of Locomotive Rehabilitation Science, Unit of Rehabilitation Sciences, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8520, Japan.
J Physiol Sci. 2013 Nov;63(6):401-8. doi: 10.1007/s12576-013-0277-4. Epub 2013 Jul 2.
This study examined mechanical and thermal hypersensitivity in the rat hind paw during cast immobilization of the hind limbs for 4 or 8 weeks and following cast removal. Blood flow, skin temperature, and volume of the rat hind paw were assessed in order to determine peripheral circulation of the hind limbs. Sensitization was analyzed by measuring the expression of the calcitonin gene-related peptide (CGRP) in the spinal dorsal horn following cast immobilization. Two weeks post immobilization, mechanical and thermal sensitivities increased significantly in all rats; however, peripheral circulation was not affected by immobilization. Cast immobilization for 8 weeks induced more serious hypersensitivity compared to cast immobilization for 4 weeks. Moreover, CGRP expression in the deeper lamina layer of the spinal dorsal horn increased in the rats immobilized for 8 weeks but not in those immobilized for 4 weeks. These findings suggest that immobilization-induced hypersensitivity develops during the immobilization period without affecting peripheral circulation. Our results also highlight the possibility that prolonged immobilization induces central sensitization in the spinal cord.
本研究在大鼠后肢固定 4 或 8 周以及固定去除后，检查了后爪的机械和热敏感性。为了确定后肢的外周循环，评估了血流、皮肤温度和大鼠后爪的体积。通过测量固定后脊髓背角降钙素基因相关肽 (CGRP) 的表达来分析敏化。固定后 2 周，所有大鼠的机械和热敏感性均显著增加；然而，固定对循环没有影响。与固定 4 周相比，固定 8 周引起更严重的过敏。此外，固定 8 周的大鼠脊髓背角深层层的 CGRP 表达增加，但固定 4 周的大鼠则没有。这些发现表明，固定引起的过敏在固定期间发展，而不影响外周循环。我们的结果还强调了长时间固定可能会导致脊髓中枢敏化的可能性。
