电针调节皮层纹状体突触可塑性在改善帕金森病大鼠运动症状时效特征中的作用

Our previous series of studies have demonstrated that high-frequency electro-acupuncture (EA) could alleviate the motor symptoms of parkinsonian animal models. Recent study has suggested that EA improve the motor symptoms in a time-dependent manner which showed the accumulative effects and long-lasting effects in PD rats. However, the mechanism remains unclear. In Parkinson's disease, enhanced glutamatergic transmission in the corticostriatal pathway is one of the prominent neurophysiologic phenomena associated with the disorder. It triggered the abnormal changes including the spine density and structure, glutamate release and synchronization of beta band oscillatory activity in the cortico-basal ganglia, which related to the symptoms of PD. So our hypothesis is: EA has a time-dependent effect on alleviating the motor symptoms, which modulates the abnormal glutamatergic transmission in the corticostriatal pathway by mediating the synaptic structural plasticity, Glu release and synchronized beta band oscillatory in corticostriatal pathway. During the different time between EA treatment and post-treatment, the effects of EA on motor behaviors were observed. Golgi staining and electron microscope were used to observe the spiny structure morphology, and microdialysis combined with HPLC were used to test the glutamate release in the striatum, and multi-channel recording were used to record populational synchrony through the cortex and striatum. In additional, approaches of chemical genetics were used to selectively activate the corticostriatal glutamatergic pathway and then the blockage effects of EA treatment on parkinsonian rats was observed. All these studies could explain the effects and mechanism of EA on alleviating the motor symptoms of PD rats in a time dependent manner.

本室研究已证实电针(EA)可改善帕金森病（PD）模型动物运动障碍，又发现EA改善PD运动症状具有时间依赖的蓄积效应和后续效应，但机制不明。皮质纹状体谷氨酸（Glu）能通路活动异常是PD重要病理特征，表现为纹状体内神经元树突棘数目及结构改变、Glu释放增强及皮质-纹状体同步化β振荡，直接导致PD运动障碍产生。本项目假说是“EA改善PD大鼠运动症状具有特定时效特征，以调节皮质-纹状体Glu能异常传递为核心，通过对Glu能突触结构可塑性、Glu释放动态平衡及皮质-纹状体同步化β振荡功能可塑性为调控途径”。拟在EA对PD大鼠治疗期及停针后不同时间点，用高尔基染色及免疫电镜观察树突棘结构可塑性，微透析动态检测Glu释放，在体多通道同步记录皮质纹状体电活动检测功能可塑性。此外，通过化学遗传学技术时间特异性地激活皮质纹状体Glu能神经元活性观察对EA治疗的阻断效应，可全面阐释EA治疗的时效特征及机制。

帕金森病（Parkinson’s disease, PD）患者存在着明显的运动障碍，其运动症状的发生机理尚不明确，并缺乏有效的治疗措施。我们长期的研究已证实电针(EA)可改善PD模型的运动障碍，机制值得深入研究。除了黑质-纹状体多巴胺能通路不可逆转的丢失之外，皮质-纹状体谷氨酸（Glu）能通路活动异常也是PD的重要病理特征。本项目围绕“EA改善PD大鼠运动症状具有特定时效特征，以调节皮质-纹状体Glu能异常传递为核心，通过对Glu能突触结构可塑性、Glu释放动态平衡及皮质-纹状体同步化β振荡功能可塑性为调控途径”展开研究。主要结果是：1 证实EA 可渐进性性改善 PD 大鼠模型运动障碍，在电针4周时效果最为显著，在停止EA两周左右仍有后续作用；2 采用高尔基染色发现EA对皮质-纹状体谷氨酸投射的突触可塑性具有同样的调节效应；3 已证实EA 在改善PD症状过程中并未逆转黑质-纹状体的DA传递，且降低了纹状体内谷氨酸的释放，EA对谷氨酸的调节也存在着同样的时效特征；4 进一步对皮层-纹状体内电生理信号的记录发现，EA可 调节皮质-纹状体同步化β振荡活动也具有类似的时效特征；5 化学遗传学手段选择性调控皮层-纹状体谷氨酸通路，进一步证实了EA的改善效应。本研究成果不仅表明电针治疗对PD症状改善的时效特征，也揭示了PD运动症状发生的皮层-纹状体环路机理，可为PD治疗提供新的治疗靶点。