聚肌胞苷酸预处理羊膜源性神经干细胞对大鼠创伤性脑损伤的治疗作用及机制研究

Traumatic brain injury (TBI) results in secondary brain injuries which lead to neurodegeneration in the injury site, in which inflammation plays an important role. So to modulate local immune response becomes an important treatment strategy for TBI. Recent studies have shed new light on the interaction between the NSCs and cells belonging to the innate and adaptive arms of the immune system. Preliminary studies found that NSCs derived from amnion can effectively reduce cavitation formation and promote functional recovery after TBI. However, its therapeutic effect remains to be further improved. Recently, there is evidence showed that activating the Toll-like receptor 3 can induce the polarization into an anti-inflammatory type. NSCs also abundantly expressed TLR 3, and TLR 3 pathways activation may enhance the immunosuppressive effects of NSCs, and then improve their therapeutic effect on TBI. In this study, the NSCs derived from amnion will be grafted into the injured animal model, after activating to Toll-like receptor 3 by polyinosinic-polycytidylic acid in vitro, to observe the treatment effect. The effect of TLR3 signal pathway on regulating the secretion of inflammatory cytokines, and its effect on macrophage polarization will be also detected. This study will open up new idea to stem cell-based treatment for TBI.

创伤性脑损伤(traumatic brain injury, TBI)造成的继发性损伤可引发损伤局部的神经退行性改变，炎症反应在其中发挥重要的作用。因此，调控损伤局部免疫反应便成为TBI一个重要治疗策略。神经干细胞(neural stem cells, NSCs)广泛参与中枢神经系统免疫反应，前期研究显示，羊膜源性神经干细胞能有效减少TBI后的空洞形成和促进功能恢复，但其治疗作用仍有待进一步提高。最新发现，激活间充质干细胞Toll样受体3(TLR3)可调控其进入抑制免疫状态。NSCs同样表达TLR3，激活其TLR3通路可能增强其免疫抑制作用，提高对TBI的治疗效果。本课题拟采用聚肌胞苷酸体外对NSCs进行预处理，观察其是否有效激活NSCs TLR3并进一步促进TBI后的功能恢复，此外对TLR3通路在调节分泌炎性因子和对巨噬细胞极化中的分子机制进行深入研究，为干细胞移植治疗TBI提供新思路。

创伤性脑损伤(traumatic brain injury, TBI)造成的继发性损伤可引发损伤局部的神经退行性改变，炎症反应在其中发挥重要的作用。因此，调控损伤局部免疫反应便成为TBI一个重要治疗策略。本研究拟阐明聚肌胞苷酸预处理羊膜源性神经干细胞在治疗TBI中的免疫调节作用及分子机制。结果显示，通过酶消法可以从足月剖宫产羊膜组织中获得间充质干细胞，其表型稳定，具有多项分化潜能，在特定条件下可向中胚层分化，通过诱导还可跨胚层分化为神经干细胞，羊膜源性神经干细胞还可进一步分化为神经元及神经胶质细胞；通过聚肌胞苷酸处理，羊膜源性神经干细胞可通过激活TLR3极化进入抑制炎症状态，抑炎性细胞因子表达及分泌水平明显增高；将其移植入TBI大鼠损伤区域后，可影响TBI损伤后的急性炎症状态，使大鼠损伤局部的炎症程度降低，并促使损伤局部巨噬细胞/小胶质细胞极化进入M2抑炎状态，从而使鼠源性抑炎因子表达水平增高，促炎因子表达水平降低；聚肌胞苷酸预处理羊膜源性神经干细胞移植组TBI大鼠神经评分高于单纯羊膜源性神经干细胞移植组，且两组均高于生理盐水组；预处理组损伤空洞体积低于单纯羊膜源性神经干细胞移植组，且两组均低于生理盐水组。我们可以得出结论，羊膜源性神经干细胞存在极化现象，激活TLR3信号通路可使其进入M2状态，移植入体内后通过与大鼠局部炎性细胞相互作用，降低局部炎症造成的神经元损伤，从而改善TBI大鼠功能恢复。