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

采用6.0丝将L5脊神经背根神经节（DRG）近端2 mm或远端2 mm结扎，并将其两个部位（即双压伤）结扎，建立腰椎神经根病大鼠模型。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神经根病变的程度。在行为学研究中，DRG损伤大鼠最为敏感，DRG远端损伤大鼠比DRG近端损伤大鼠更为敏感。大鼠L5节段水平I-II级小胶质细胞的激活数量和EPSC的振幅和频率随行为研究的增加呈相同的顺序增加。双挤压模型与DRG损伤模型无显著性差异。此外，我们发现腰交感神经切除术降低了DRG损伤模型的机械敏感性和EPSC的频率。

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.