Neuronal Modulation after long term forepaw immobilization in rats.

长期铸造固定偶尔会引起固定侧的病理性疼痛状态。固定相关疼痛的潜在神经生理机制尚不清楚。为此，我们专门研究了长期固定模型铸造5周后，降钙素基因相关肽（CGRP）在背根神经节（DRG）、脊髓背角和后核（楔状核）中的表达变化。右下肢从前臂到前爪用塑料石膏包绕，使腕关节保持90度屈曲。在该模型中，尽管CGRP免疫反应（CGRP- ir）神经元的数量没有差异，但与对侧相比，固定侧（同侧）的CGRP分布在更大的DRG神经元中。与对侧相比，同侧III-V椎板，而非I-II椎板的CGRP表达显著升高。此外，长期固定后GFSP和CD11b的表达增加。这些结果表明，长期铸造后除了关节挛缩外，还发生了神经元的塑性改变。正常前爪加铸是改善前爪弃用行为的有效方法。因此，充分的肌肉骨骼康复是必不可少的治疗。

Long-term immobilization by casting can occasionally cause pathologic pain states in the immobilized side. The underlying neurophysiological mechanisms of immobilization-related pain are not well understood. For this reason, we specifically examined changes of calcitonin gene-related peptide (CGRP) expression in the dorsal root ganglion (DRG), spinal dorsal horn and posterior nuclei (cuneate nuclei) ina long-term immobilization model following casting for 5 weeks. A plastic cast was wrapped around the right limb from the forearm to the forepaw to keep wrist joint at 90 degree of flexion. In this model, CGRP in immobilized (ipsilateral) side was distributed in larger DRG neurons compared with contralateral side, even though the number of CGRP-immunoreactive (CGRP-IR) neurons did not differ. Spinal laminae III-V, not laminae I-II in ipsilateral side showed significantly high CGRP expression relative to contralateral side. In addition expression of GFSP and CD11b were increased after long term immobilization. These results suggest that neuronal plastic changes were occurred after long term casting addition to joint contracture. Additional casting to sound forepaw was useful method to improve disuse behavior after the cast treatment. Thus adequate musculoskeletal rehabilitation was essential for the treatment.