Elucidation of the pain mechanisms in the extra-foraminal and double crush lesions of the L5 spinal nerve

用6.0丝线结扎L5脊神经背根节（DRG）近端2 mm或远端2 mm处，并将其两个部位（即双侧挤压）造成腰神经根病大鼠模型。术后7天，我们使用机械敏感性、免疫组织化学和体内膜片钳记录检查了神经根病的程度。在行为学研究中，损伤背根节的大鼠最敏感，损伤背根节远端的大鼠比损伤背根节近端的大鼠更敏感。大鼠L5节段Ⅰ-Ⅱ层小胶质细胞活化数及EPSC的振幅和频率与行为学研究结果一致。双侧挤压伤模型与DRG损伤模型比较无显著性差异。此外，我们还发现腰交感神经节切除可降低背根节损伤模型的机械敏感性和EPSC频率。

The lumbar radiculopathy rat model was created by ligating the dorsal root ganglia (DRG) of the L5 spinal nerve, 2 mm proximal to the DRG or 2 mm distal to the DRG, and the two sites of them (i.e. double crush) with 6.0 silk. We examined the degree of the radiculopathy using mechanical sensitivity, immunohistochemistry and in vivo patch-clamp recordings, 7 days after surgery. The rats injured the DRG was most sensitive, and the rats injured distal to the DRG were more sensitive than those rats injured proximal to the DRG in the behavioral study. The number of activated microglia in laminas I-II of the L5 segmental level and the amplitudes and frequencies of EPSC in the rats increased in the same order with the behavioral study. There was no significant difference between the double crush models and the DRG injured model. Moreover, we found that lumbar sympathectomy decreased the mechanical sensitivity and the frequencies of EPSC in the DRG injured model.