中文摘要：

目的：观察降钙素基因相关肽（calcitonin gene-related peptide，CGRP）样阳性终末在L5脊神经结扎模型大鼠脊髓背角浅层内的表达变化。方法：建立大鼠L5脊神经结扎模型（L5 spinal nerve ligation model，SNL），建模后分别在1、3、5、7d和14d不同时间点通过vonFrey丝检测大鼠后爪的机械性痛敏，然后在大鼠分别存活7d和14d时灌注取材，采用免疫组织化学染色结合平均光密度（optical density，OD）分析的方法以及免疫电镜标记技术检测脊髓背角浅层内CGRP样阳性物质的表达变化。结果：（1）行为学结果显示：模型组大鼠的机械性痛敏的阈值明显降低，与正常组比较有显著性差异（P〈0．05），提示建模成功；（2）免疫组织化学染色显示：正常大鼠脊髓背角浅层内存在大量密集分布的CGRP样阳性终末，主要分布于脊髓背角的Ⅰ层和Ⅱ层。SNL模型大鼠在结扎7d和14d后脊髓背角浅层内CGRP样阳性产物的表达明显增多，其平均OD值分别为38．30±3．11和35．70±2．36，与正常对照组（25．10±2．30）比较，具有显著性差异（P〈0．05）；（3）电镜结果显示：CGRP样免疫活性物质只分布于轴突终末内，且主要与树突结构形成非对称性突触。结论：CGRP样免疫阳性物质在SNL模型大鼠脊髓背角浅层内的表达增加，提示CGRP样阳性终末在伤害性信息的传递中具有重要作用。

英文摘要：

Objective： To observe the expression change of ealcitonin gene-related peptide （CGRP）-immunoreactive terminals in the superficial laminae of spinal dorsal horn （SDH） in a rat spinal nerve ligation model （SNL）. Methods： The rat model of the L5 spinal nerve ligation was set up and the ipsilateral hind paw mechanical withdrawal threshold of the rats was assessed with yon Frey filament on time of 1, 3, 5 , 7 and 14 days after operation. The rats were sacrificed on 7 or 14 days after operation. Immunohistochemistry combined with average optical density（OD） analysis and immune- electron microscope technique were performed to examine the expression of CGRP-immunoreactivity in the superficial lam- inae of spinal dorsal horn of L5 segment . Results ： （ 1 ） Behavior test results demonstrated that the hind paw withdrawal threshold of the SNL modal rats significantly reduced compared with the control group （ P 〈 0.05 ）. （2） The immunohis- tochemical stain results showed that a large number of CGRP immunoreactive terminals were intensively distributed in the superfical lamina of SDH especially in laminae I and II for rats in the control group. After L5 spinal nerve ligation for 7 or 14 days, the amount of CGRP immunoreactivities in the superfical lamina of SDH were obviously increased, and the average optical density of the two groups showed 38.30 ± 3.11 and 35.70 ± 2.36 respectively, which were remarkably higher than 25.10 ± 2.30 （ P 〈 0.05 ） of the control group. （ 3 ） Electron microscopy results showed that CGRP-immunorectivi- ties were expressed in the axon terminals and mainly formed the asymmetric synaptic connection with the dendrites of neu- rons. Conclusion： The increased expression of the CGRP-immunoreactivity in the SNL model rats suggest that the CGRP positive terminals might play an important role in nociceptive information transmission.