晚期周围神经损伤后感觉功能恢复中:脊髓后角P物质及降钙素基因相关肽的变化

背景晚期周围神经损伤有无修复价值?如果脊髓神经元中P物质和降钙素基因相关肽的变化发生了不可逆的变化,其修复后也预示着感觉功能的缺失. 目的定量研究周围神经损伤24周后,脊髓后角中P物质和降钙素基因相关肽的变化.设计建立以大鼠坐骨神经损伤为研究对象的实验模型,损伤后24周为最远期观察点,自身对照(对侧空白组),定量化研究.单位第四军医大学骨科研究所.材料实验于2002-10/2003-05在第四军医大学骨科研究所完成.SD大鼠55只,分成11组,即坐骨神经切断1,2,3,4,6,8,10,12,16,20,24周各组.干预切断大鼠一侧坐骨神经并结扎其近端的方法建立周围神经损伤模型;另一侧为对照侧.应用计算机图像分析技术测试P物质和降钙素基因相关肽免疫反应区的面积.主要观察指标各组大鼠脊髓后角中P物质和降钙素基因相关肽阳性纤维的终末分布面积的变化.结果55只大鼠均进入结果分析.①P物质时间序列表示周围神经损伤后2～6周,P物质在脊髓后角免疫反应区面积下降至最低,随之回升,至16周恢复正常,20,24周无明显的进一步变化.②脊髓后角降钙素基因相关肽阳性纤维和终末分布面积损伤与自身对照侧的比值1周时1.14,6周时1.13,24周时0.29,各时间点基本相似(P＞0.05)结论周围神经损伤至晚期,脊髓后角及后根神经节细胞合成和分泌P物质及降钙素基因相关肽的功能尚未受到破坏,脊髓后角已处于一种稳定的平衡状态,仍有恢复感觉功能的神经学基础.

Changes of substance P and calcitonin gene-related peptide in rat spinal dorsal horn during feeling function recovery after late stage peripheral nerve injury

BACKGROUND: Whether the injured peripheral nerve in a late stage has repairing value still remains a problem. If irreversible changes happen in substance P and calcitonin gene-related peptide, the feeling function will lose even after repairing.OBJECTIVE: To quantitatively study the changes of substance P(SP) and calcitonin gene-related peptide(CGRP) in the spinal dorsal horn 24 weeks after peripheral nerve injury.DESIGN: A self-controlled quantitative experiment.SETTING: Institute of Orthopaedics of the Fourth Military Medical University of Chinese PLA.MATERIALS: This experiment was performed in the Institute of Orthopaedics of the Fourth Military Medical University of Chinese PLA from October 2002 to May 2003. Totally 55 SD rats were divided into 11 groups according to time points(1, 2, 3, 4, 6, 8, 10, 12, 16, 20 and 24 weeks after sciatic nerve transection).INTERVENTIONS: Sciatic nerve injury model was set up by transecting one side of sciatic nerve and ligating the proximal stump of sciatic nerve; the other side was set as the control side. Computer-assisted image analysis was used to measure the immunologic reaction areas of substance P and CGRP.MAIN OUTCOME MEASURES: Changes of the distribution of the positive fibres of SP and CGRP in rat spinal dorsal horn in each group.RESULTS: Fifty-five rats entered the result analysis. The distributions of SP immunoreactivity in the spinal dorsal horn following sciatic nerve injury showed a significant reduction during 2-6 weeks, followed by a slow rate of increase,and reached almost complete restoration at 16 weeks after deafferentation. No obvious advanced changes happened at 20 and 24 weeks. The ratios for ipsilateral and cotralateral sides of positive fibre and distribution area injury in spinal dorsal horn CGRP were 1.14 at week 1, 1.13 at week 6, and 0. 29 at week 24. The ratios were similar at each time point( P ＞ 0. 05).CONCLUSION: At the late stage of peripheral nerve injury, neurons in the spinal dorsal horn and dorsal root ganglion still remain their functions to synthesize and secrete SP and CGRP. Spinal dorsal horn remains at a balanced status and still has the neurologic basis to recover the sensory function.