胆碱能抗炎通路活动调节脑梗死后皮质脊髓束可塑性及其机制研究

Although early recanalization treatment for acute cerebral ischemic stroke has made progress, most patients with stroke still have neurological functions' disability, which causes large social and economical burden to the human beings. The patients after stroke could slowly recovery their physical and neurological functions within several month, which indicates the promoting of plasticity of corticospinal tracts(CST) could facilitate the recovery of neurological functions. Vagus Nerve Stimulation (VNS) has been proved to have effect on several anti-inflammatory pathways(CAP). In our previous study, we found that VNS could facilitate the recovery of neurological functions which could not be explained just by the reaction of anti-inflammatory. So we speculated that CAP may improve the plasticity of CST and facilitate the neurological functions' recovery. In this study, MCAO model of rats and its cerebral cortex neurons will be used to develop the animal and cell models and will demonstrate if the manipulating of CAP could have an impact on the plasticity of CST and neurological functions. We will also explore the mechanism of ALk-5 dependent TGF-β signal pathway in this procedure. All these studies will provide fundamental basis for supplement therapy of the recovery of patients with stroke

尽管超早期血管再通治疗取得进展，大部分脑梗死患者仍遗留神经功能障碍，给家庭社会造成巨大的经济和精神负担。脑梗死患者病后肢体运动功能障碍有一定程度恢复，说明其恢复期损伤的皮质脊髓束（CST）存在可塑性，改善这种可塑性将促进神经功能障碍的恢复。迷走神经电刺激（VNS）可通过激活a7nAchR影响胆碱能抗炎通路(CAP)的活动，我们前期研究发现在脑梗死恢复期持续给与VNS可促进脑梗死缺损神经功能的恢复，不能以单纯的拮抗炎症反应来解释，推测CAP调控皮质脊髓束可塑性，促进运动功能的恢复。本研究采用大鼠MCAO 模型结合大脑皮质神经元培养的细胞模型，从整体、组织、细胞分子水平研究验证脑梗死后恢复期调控CAP（迷走神经电刺激，RNAi 技术抑制或切断迷走神经）对CST可塑性和前肢运动功能的影响，探讨Alk-5依赖TGF-β信号通路活动在其中的作用，为脑梗死患恢复期补充治疗方式研究提供理论依据。

大部分脑梗死患者常遗留有明显的运动功能障碍，脑梗死后迷走神经电刺激（VNS）可通过激活烟碱型乙酰胆碱受体a7(a7nAchR)影响胆碱能抗炎通路（CAP）的活动，调控CAP的活动影响皮质脊髓束（CST）可塑性以及血管生成可能在脑梗死后运动功能康复中发挥重要作用。我们应用右侧大脑中动脉阻塞（MCAO）大鼠脑梗死模型对脑缺血后应用经皮迷走神经电刺激（ta-VNS）调控CAP活动变化影响CST可塑性、血管生成及其病理生理机制进行了研究，发现：（1）脑梗死后CAP 的关键受体a7nAchR主要定位在神经元和星型胶质细胞，且其表达下调，ta-VNS可逆转其下调趋势，继而激活CAP活动。（2）促进中枢CAP活动（ta-VNS）与脑缺血后运动功能恢复密切相关，我们选取7天，14天和28天来检测运动功能的恢复情况，发现CAP的激活在脑梗死后至少1月内对运动功能恢复有改善作用。（3）CAP的活动变化与脑缺血后CST可塑性、血管生成及大鼠前肢运动功能的恢复密切相关，利用a7nAchR功能拮抗剂阻断CAP活动消除ta-VNS对CST可塑性、血管再生的促进作用。（4）激活中枢的CAP活动（ta-VNS）通过PPAR-γ促进脑缺血后的轴突可塑性、血管新生；（5）促进中枢CAP活动（ta-VNS）可以上调ALK5的表达；Alk-5依赖TGF-β信号通路激活通过调控Gadd45b促进神经生发。研究发现丰富了脑梗死恢复期肢体运动功能康复病理生理机制的认识。ta-VNS可通过调控CAP活动及其下游PPAR-γ、ALK5等信号通路的活动促进神经血管单位的重塑和运动功能恢复，为其临床应用研究提供了理论依据。