大鼠坐骨神经损伤后早期脊髓背角小胶质细胞活化状态和活化类型的变化规律

目的 研究坐骨神经损伤后脊髓背角小胶质细胞活化状态和活化类型的变化规律。方法 大鼠随机分为对照组(n=24)、实验组(n=24)。实验组采用结扎坐骨神经主干的方法构建大鼠坐骨神经损伤模型。测量大鼠疼痛行为学数据,于术后第1,7,14天取材,采用免疫荧光染色技术检测大鼠腰段脊髓背角不同激活状态的小胶质细胞变化;通过qRT-PCR验证不同类型小胶质细胞相关标记物的变化趋势。结果 假手术组大鼠在术后14 d内脊髓背角小胶质细胞形态和数量无明显改变,小胶质细胞标记物也无明显变化。术后1 d,CCI大鼠小胶质细胞形态和数量无明显变化,但促炎型(M1型)标记物增加,提示M1型小胶质细胞活化。术后7 d和14 d,CCI大鼠小胶质细胞数量显著增加,标记物检测显示以M1型活化为主,抑炎型(M2型)小胶质细胞活化不明显。结论 大鼠脊髓背角小胶质细胞在坐骨神经损伤后早期即开始活化,活化持续到至少术后两周,在此期间均以M1型小胶质细胞活化为主。

Differential activation of microglial in rats spinal dorsal horn at the early stage following sciatic nerve injury

Objective To study the type variation of microglial activation in spinal dorsal horn of rats after sciatic nerve injury. Methods Healthy adult male Sprague-Dawley rats were randomly divided into the control and experimental groups, 24 rats in each group. The experimental group underwent ligation of sciatic nerve trunk to generate nerve injury in the rats. The pain behavior in the rats was measured at the 1th, 7th and 14th postoperative days, and the changes of microglial activation in the rat lumbar spinal cord dorsal horn was detected by immunofluorescence staining. qRT-PCR assay was used to validate the activation trends of M1 and M2 types of microglia cells. Results No significant changes were found in the microglial cells in the spinal cord dorsal horn of rats in the sham-operation group during 14 days after operation. In the sciatic nerve ligation group at 1 day after operation, no significant change was observed in the number of microglial cells, but the expression of marker of M1 microglia was significantly increased. At 7 and 14 days after operation, the number of microglial cells and the expression of M1 microglia marker in the spinal cord dorsal horn were increased significantly. Conclusions Microglia activation in the spinal dorsal horn starts at the first day after sciatic nerve injury, and lasts at least for two weeks after the operation. M1 microglia activation dominates during this period.