脑缺血后强制性运动通过NMDA/CaMKII通路调控突触重塑的机制研究

"Learned non-use", caused by repeated failure with the affected limbs and easier access to the unaffected limbs after brain lesion, often presents in post-stroke patients. Constraint-induced movement therapy (CIMT) emphasizes intensive use of the affected limbs by restraining the unaffected limbs, aiming at treating learned non-use. In our previous studies, we found that the function of the paralysed limbs were greatly improved; the structure of synapes in the brain were conserved; and, brain-derived neurotrophic factor (BDNF) and synapsin I were increased after CIMT in cerebral ischemic rats. According to our clinical observations and results obtained in our previous studies, we hypothesise that the mechanism of CIMT after stroke lies in facilitating brain plasticity and remodeling connections between synapses. Therefore, in the present study, micro PET, the most advanced and accurate method to observe brain stimulation by identifying glycometabolism in live rodents, is adopted in order to find out which brain area responds to CIMT. Then, neural labiling and retrograde technique will be used to dicover neuron growth, differentiation and synaptic remodeling in those regions. To explain how the above dynamic plasticity occurre, NMDA/CaMKII pathway is thought to be most relative pathway mediating this. Because NMDA/CaMKII is universally recognized as the most important biomarker for synaptic growth and function as well as brain plasticity. So, NMDA/CaMKII and relavent proteins in the pathway will be tested to explore the underlying molecular mechanism for brain plasticity induced by CIMT. The highlight of this study is that it's a new point of view explaining how CIMT works in treating paralysis after stroke based on both clinical and experimental observations.

躯体在大脑皮层代表区的大小取决于该部分的使用强度和动作的复杂程度。强制性运动疗法（CIMT）要求反复强化使用患肢，避免或矫正习得性废用，在中枢性上肢瘫中疗效明显。本研究认为CIMT起效机制很可能为诱导了中枢内突触重塑。本研究前期结果显示CIMT明显改善上肢功能，保护突触结构、调节突触新生(BDNF上调)并提高突触小泡含量(SynI上调)以加强信号传导效能而发挥治疗作用。因此，本研究首先拟通过micro PET- - 目前最直观地观测活体动物脑区激活的方法- - 为脑缺血后CIMT对脑激活区改变提供直观的证据；进而，通过神经细胞标记和示踪技术对CIMT后神经细胞增殖分化和投射情况进行分析。NMDA受体与突触生长和功能密切相关，也是目前国内外大脑可塑性与突触功能研究的热点。最后，本研究拟通过观测NMDA/CaMKII通路及其下游蛋白分子变化揭示脑缺血后CIMT调控突触重塑的分子机制。

躯体在大脑皮层代表区的大小取决于该部分的使用强度和动作的复杂程度。强制性运动疗法（CIMT）要求反复强化使用患肢，避免或矫正习得性废用，在中枢性上肢瘫中疗效明显。本研究认为CIMT起效机制很可能为诱导了中枢内突触重塑。本研究前期结果显示CIMT明显改善上肢功能，保护突触结构、调节突触新生(BDNF上调)并提高突触小泡含量(SynI上调)以加强信号传导效能而发挥治疗作用。本研究首先通过micro PET--目前最直观地观测活体动物脑区激活的方法--为脑缺血后CIMT对脑激活区改变提供直观的证据，本研究通过micro PET 成像发现，CIMT组大鼠患侧上肢的功能改善优于对照组，且健侧半球岛叶和伏隔核的代谢明显高于对照组，意味着健侧情绪相关脑区的代偿可以在CIMT诱导的功能恢复中发挥重要的作用。ERK通路相关蛋白在脑缺血后的功能恢复起到重要作用，本研究通过观测ERK通路及其蛋白分子变化揭示脑缺血后CIMT可以明显改善患侧上肢的功能，降低了双侧皮层和海马区域p-ERK的表达以及患侧海马区域JNK和P-JNK的表达。