小胶质细胞在中枢神经系统创伤后的双重作用及调控机制

小胶质细胞是中枢神经系统的固有免疫细胞，在脑或脊髓创伤后的神经炎症反应中起关键作用。神经系统损伤后小胶质细胞可提供神经保护因子，清除细胞碎片并调控神经修补过程。而另一方面，小胶质细胞会产生高水平的促炎及细胞毒性介质从而阻碍CNS修复，促使神经元失能及细胞死亡。小胶质细胞的双重特性可能与其损伤后的表型及功能反应有关。本综述探讨近年来有关脑和脊髓损伤后小胶质细胞活化表型的研究，以及小胶质细胞在神经元、血管、少突胶质细胞生长及再生中的可能发挥的作用。并简述已知的调控表型转换的分子机制，着重探讨可以影响小胶质细胞活化状态的治疗途径。了解小胶质细胞表型调控机制有助于我们增加神经系统损伤恢复的知识，并提供新的治疗策略。

The dual function of microglia and their regulatory mechanisms after central nervous system injury

Microglia is the innate immunocyte in the central nervous system, playing an important role in neuroinflammations after brain or spinal cord injury. By providing neurotrophic factors and removing cellular debris microglia can regulate nervous repair. However, high levels of pro-inflammation and neurotoxic factors produced by microglia hinder the CNS repair, and prompt neuron incapacity and cell death. The dual nature of microglia is related to their diverse phenotypes after injury. In this review, we focus on recent researches about the phenotypes of activated microglia after brain or spinal cord injury, as well as their effects on neurogenesis, oligodendrogenesis, and angiogenesis. The molecular signals controlling the switch of the phenotypes are discussed. We also highlight the possible therapeutic pathways which can change the activation statements of microglia. Better understanding of mechanisms regulating microglia phenotypes may contribute to our knowledge about repair and restoration of the nervous system, and provide new therapeutic strategies.