脑梗死后远隔神经网络位点的分子调控机制和fMRI基础研究

After cerebral infarction, a large number of neuronal cells were necrotic and complex connection of neural network was severely impaired and hypofunction. There were numerous patients with various kinds of sequela even they already got standardized treatment. It is manifested that function inhibition of the neural network after cerebral infarction is a response indicators to a treatment effect in patients of functional recovery and prognosis, whereas the regulatory mechanism of the neural network site is unclear. How could save the neural network function effectively becomes the key to the neurological rehabilitation after cerebral infarction. The main content of this research is based on the mechanism of neural network impairment after cerebral infarction, using RNAi (RNA interfere) technology to observe the role of the RGMb (repulsive guidance molecule b) and NMDAR (N-methyl-D-aspartate receptor) in axon regeneration, synaptic plasticity and cell apoptosis in the primary lesion and remote regions in rat model. Moreover, fMRI technology had been used to monitor in vivo before and after RNA intervention continuously, and explore the pathophysiological mechanisms of the outcome and development of neural network impairment after cerebral infarction. The value of fMRI technology to monitor the neural network after cerebral infarction would be discussed and provide the theoretical basis for the molecular regulation mechanism.

脑梗死后大量神经细胞死亡，神经网络的复杂联系也受到严重损害而导致功能减退，即使经过规范化治疗，患者仍有可能遗留不同程度后遗症。既往研究表明：脑梗死后出现远隔部位功能抑制是反映患者治疗效果、功能恢复及提示预后的重要指标，但其神经网络位点调控机制目前尚不清楚。因此，如何有效挽救脑梗死后的神经网络功能，成为脑梗死后神经康复的关键之一。本课题以脑梗死后神经网络损伤的发生机制为主要研究内容，应用RNAi技术，通过基因水平进行正向及负向干预，观察干预前后排斥导向分子RGMb和兴奋性氨基酸受体NMDAR在大鼠脑梗死原发灶及远隔部位介导的轴突再生、突触重塑和细胞凋亡的调控作用，同时应用fMRI技术对干预前后进行连续无创性活体监测，进一步探寻脑梗死及神经网络损伤发生、发展及转归的病理生理机制，探讨fMRI技术对脑梗死后远隔位点功能改变的监测价值，为脑梗死后远隔神经网络位点分子调控机制深入研究提供理论支撑。

脑梗死以其高发病率、高死亡率、高致残率成为全球一大公共卫生问题，其造成的功能缺陷包括梗死核心区内的神经元死亡以及邻近和远隔脑组织的继发性损伤，神经机能联系不能被用于描述远离原发损伤部位的脑功能或代谢下降现象。临床研究表明,继发性远隔部位损伤与神经症状学之间存在联系，对于脑梗死后远隔区域的继发神经损伤及功能、代谢异常的干预和治疗近年更引起了广泛关注，基于这种现象的针对性治疗或将改善患者预后。本课题以脑梗死后梗死核心区以及邻近和远隔脑组织神经损伤为主要研究内容，以RGMb特异性RNAi重组腺病毒通过基因水平进行干预，观察干预前后排斥导向分子RGMb和兴奋性氨基酸受体NMDAR在大鼠脑梗死原发灶及远隔部位介导的轴突再生、突触重塑和细胞凋亡的调控作用，同时应用功能磁共振技术对干预前后进行连续无创性活体监测，探寻脑梗死及神经网络损伤发生、发展及转归的病理生理机制。本课题经研究发现脑梗死后NMDAR、RGMb表达增加，参与神经细胞凋亡演变，且与神经功能评分和远隔脑区磁共振参数变化相关，间接说明其可能参与脑梗死后神经损伤过程和神经机能联系不能现象的发生。给予RGMb特异性RNAi干预治疗后，梗死核心区及对侧小脑RGMb表达降低，说明该方法对脑梗死后神经功能减低有积极的治疗意义。磁共振扩散峰度成像可检测脑梗死后梗死区及远隔区域的参数变化，氢质子波谱成像术后各组大鼠脑Naa、Cr、Cho峰值持续下降，提示功能磁共振成像技术在脑梗死后神经机能损伤演变过程中的无创性检测价值。本课题以新的思路从发病机理的初始关键环节着手，观察轴突生长抑制剂介导的轴突破坏、突触重塑和神经元凋亡对神经网络的调控机制，并通过生物干扰技术阻断靶蛋白的表达而达到预防脑梗死后神经网络位点功能抑制的目的，并以先进功能磁共振技术综合应用提供影像学参数指标，为脑梗死的治疗、预后及神经康复提供新的无创性监测手段。