极化巨噬细胞对脊髓损伤后内源性神经干细胞动员、增殖和分化的分子机制研究

The distruction of the nerve cells, especially the motor neurons and neural circuits caused by SCI is the direct cause of nerve dysfunction. Thus, creation of a permissive environment for NSC is a promising strategy to replace lost neuronal cells, promote repair, and stimulate functional plasticity after SCI. Immune inflammatory response is not only one of the most important pathological process and is As the most important pathological process after SCI, Inflammation is naturally one of the important factors that control the environment within the injured spinal cord. Macrophages as the main effector cells involved in that process, can directly influence the environment and the prognosis after spinal cord injury.. In our previous study, we found that the co-transplanted NS/PCs showed enhanced astrocytic versus neuronal/oligodendrocytic differentiation in the presence of bone marrow-derived M1- versus M2- polarized macrophages. Here, the project proposed on the basis of previous studies is designed to further discuss the mechanism of the polarized macrophages effect on the mobilization, proliferation and differentiation of endogenous NSCs in after SCI. In order to complete the study,we will regulate the polarized macrophages in the inyured spinal cord in different pathologic stages after SCI and simultaneously specific track endogenous neural stem cells in the spinal cord using a variety of transgenic mice, flow cytometry sorting, immunohistochemical staining and related molecular biology methods. This study is of great significance for us to understand the function of polarized macrophages on endougenous neural stem cells after SCI.Through this research , we hope we can provide important theoretical basis in the treatment of SCI ,including creation a permissive environment for endougenous NSC and the right treatment time to promote neurogenesis.

SCI造成神经细胞尤其是运动神经元的缺失及神经环路的破坏是导致神经功能障碍的直接原因。为脊髓内源性NSC创造适合神经发生的内环境促使NSC发挥细胞替代作用是治疗SCI最简便有效的策略之一。活化的巨噬细胞是SCI后炎症反应中最主要的效应细胞，直接影响着损伤脊髓内环境及脊髓损伤的预后。.申请人前期研究发现：M1巨噬细胞会促使移植的NSC向星形胶质细胞分化；而M2巨噬细胞则有利于外源性NSC分化成神经元和少突胶质细胞。本项目拟在前期研究的基础上，特异性追踪脊髓内源性神经干细胞，并通过在SCI 的不同病理进程调控损伤区巨噬细胞的极化，进一步探讨M1和M2极化巨噬细胞对脊髓内源性NSC的动员、增殖和分化影响及分子机制。本研究对进一步揭示SCI后极化巨噬细胞对脊髓内源性神经干细胞的功能具有重要意义，将为找到促进神经发生的内环境、最佳时间窗以及今后利用脊髓内源性NSC治疗SCI提供重要的理论依据。

SCI造成神经细胞尤其是运动神经元的缺失及神经环路的破坏是导致神经功能障碍的直接原因。为脊髓内源性NSC创造适合神经发生的内环境促使NSC发挥细胞替代作用是治疗SCI最简便有效的策略之一。活化的巨噬细胞是SCI后炎症反应中最主要的效应细胞，直接影响着损伤脊髓内环境及脊髓损伤的预后。.本课题主要开展了（1）醛糖还原酶AR及810nm弱激光调控巨噬细胞；（2）干预巨噬细胞极化对神经干细胞及小鼠运动功能的影响；（3）揭示极化巨噬细胞促进小鼠脊髓损伤修复的机制三部分内容研究。通过本课题的研究，我们发现小鼠脊髓损伤后损伤区的巨噬细胞高表达AR，抑制或敲除AR有利于损伤区巨噬细胞向M2型极化，以M2型巨噬细胞为主导的炎症环境有利于促进神经干细胞向神经元分化，进而促进小鼠脊髓损伤后运动功能恢复。另外我们还发现另外一种有效干预巨噬细胞极化的方法：810nm 弱激光可能会通过下调 p-NF-κB p65 的表达，抑制M1 型巨噬细胞极化。.本项目的意义主要体现在：（1）提供AR对SCI治疗作用的理论依据。AR是醛酮还原酶家族成员之一，能催化葡萄糖生成山梨醇，是多元醇代谢通路中的限速酶。很多研究显示AR除参与多元醇通路外还参与多种炎症反应的调节，我们的实验结果阐明了AR在调控SCI炎症反应中发挥重要作用。AR作为SCI后控制小胶质/巨噬细胞极化的开关基因，调控AR的药物或分子可能会成为SCI有效的治疗方法。AR抑制剂虽然可以直接抑制醛糖还原酶表达，但目前在SCI治疗中具有明显的副作用，开发新型的AR抑制剂是也治疗SCI的可行策略之一。（2）提示新型SCI治疗手段：810nm 弱激光可作为脊髓损伤区巨噬细胞极化方便可行的调控手段。.