中枢内神经胶质细胞对周围神经损伤后的反应

RESPONSE OF NEUROGLIA IN CNS TO PERIPHERAL NERVES INJURY

目的:探讨中枢神经胶质细胞对周围神经损伤反应。方法:用Thymosinβ4抗体标记小胶质细胞、Glialfibrillayacidic(GFAP)抗体标记星形胶质细胞和CarbonicAnhydrase抗体标记少突胶质细胞,在大鼠坐骨神经切断后1、2、3、4、6、8、10、12、14、18、20d,检测其脊髓及脑干内小胶质细胞、星形胶质细胞、少突胶质细胞变化情况,并对有变化者用电镜观察。结果:发现在坐骨神经损伤后第1天开始至第20天,在相应脊髓节段同侧灰质及脑干的薄束核内见到许多体积增大、数量增多的Thymosinβ4标记阳性细胞即激活的小胶质细胞;而星形胶质细胞、少突胶质细胞未见有明显改变。激活的小胶质细胞数量在损伤后第3天达到高峰,然后逐渐下降;与相应脊髓节段相比较,薄束核内激活的小胶质细胞数量要少些。电镜观察发现,这些激活的小胶质细胞多位于神经元胞体的周围,超微结构上未见有吞噬功能的形态特征。结论:周围神经损伤,引起相应中枢部位的小胶质细胞激活与增殖而没有引起其它胶质细胞的明显变化,其作用可能与保护受损的神经元、维护神经元的周围环境有关。

Objective：The aim of the study was to explore the response of neuroglia in CNS on peripheral nerves injury. Methods ：The present study has examined microglia proliferation by thymosin β4, astrocyte by antibody of GFAP and oligodendrocyte by Carbonic Anhydrase Ⅱafter sciatic nerve transection in the adult rat and was observed by using electron microscopic method. Result： Microglial activation and proliferation were observed at day 1, 2, 3, 4, 6, 8, 10, 12, 18 and 20 in CNS projection areas-spinal segment and nucleus gracilis after sciatic nerve transection. Microglial activation and proliferation had peak in the day 3 post injury. The numbers of thymosin β4-labeled microglia were lower in the nucleus gracilis compared to the lumber spinal cord. Electron micrograph show that activating and proliferating microglia were often found in a perineuronal position and some of them contracted with neuron in anterior horn of spinal cord. Conclusion ：The results show that the peripheral nerve injury induce only microglia activation and proliferation in CNS projection areas.