PAG中P2X3受体介导电针缓解IBS小鼠内脏高敏感的作用机制研究

Irritable bowel syndrome (IBS) is a common clinical gastrointestinal disorder, which seriously affects the quality of life of patients. Visceral hypersensitivity is one of the main pathological characteristics of IBS. The clinical effect of electroacupuncture on IBS is definite, while the in vivo observation of the neural mechanism of acupuncture regulating the center sensitization of visceral pain has not been reported. The periaqueductal gray (PAG) - rostral ventromedial medulla (RVM) is an important downward pain regulation pathway of the central nervous system, in which the role of PAG is particularly prominent. The excitation of Glu neurons in vlPAG or the inhibition of GABA neurons can cause analgesic effect. On the contrary, it will lead to the facilitation of pain, and the activation of P2X3 receptor in PAG can improve the pain threshold. We have partially explained the peripheral sensitization mechanism of P2X3 mediated electroacupuncture in the treatment of IBS visceral hypersensitivity. For further reveals the scientific connotation of the theory of the viscera of TCM meridians, we intend to analyze the central mechanism of P2X3 receptor mediated electroacupuncture regulating the dynamic equilibrium of Glu and GABA neurons in vlPAG of IBS mice, and reveal the neurological mechanism of electroacupuncture regulating the activity of PAG neuron in the treatment of visceral pain furtherly though behavioral science, electrophysiology, photochemical genetics, chemical genetics, molecular biology technology.

肠易激综合征（IBS）是临床常见的胃肠功能紊乱性疾病，严重影响患者生活质量。内脏高敏感是其主要病理特征之一，临床电针治疗IBS疗效确切，目前尚未见针灸调节内脏痛中枢敏化的在体神经机制报道。中脑导水管周围灰质（PAG）-延髓头端腹内侧核（RVM）是中枢神经系统重要的下行疼痛调控通路，其中PAG的作用尤为突出。vlPAG内Glu能神经元兴奋或GABA能神经元抑制可以引起镇痛效应，相反，则会导致疼痛的易化，激活PAG脑区P2X3受体能提高痛阈。我们已部分阐释P2X3介导电针治疗IBS内脏高敏感外周敏化机制。为深入揭示中医经穴脏腑相关理论的科学内涵，本课题采用行为学、电生理学、光遗传学、化学遗传学、分子生物学技术，在体时空特异性操控特定脑区与细胞亚群，解析P2X3受体介导电针调节IBS小鼠vlPAG内Glu/GABA能神经元动态平衡的中枢机制，深入揭示电针调控PAG神经元活动治疗内脏痛的神经机制。

本项目通过行为学、电生理学、光遗传学、化学遗传学、分子生物学技术，在体时空特异性操控特定脑区与细胞亚群，解析P2X3受体介导电针调节IBS小鼠vlPAG内Glu/GABA能神经元动态平衡的中枢机制。研究结果发现：1）给予不同压力的CRD刺激时，vlPAG谷氨酸能神经元会被激活，但IBS模型小鼠vlPAG脑区谷氨酸能神经元激活的程度较正常小鼠低，而电针干预后vlPAG脑区谷氨酸能神经元激活的程度较模型小鼠高；2）给予不同压力的CRD刺激时，vlPAG脑区GABA能神经元会被激活，但IBS模型小鼠vlPAG脑区GABA能神经元激活的程度较正常小鼠高，而电针干预后vlPAG脑区谷氨酸能神经元激活的程度较模型小鼠低；3）光遗传和化学遗传激活vlPAG内谷氨酸能神经元时IBS内脏痛动物模型的痛阈升高，抑制vlPAG内Glu能神经元时IBS内脏痛动物模型的痛阈降低；4）光遗传和化学遗传激活vlPAG内GABA能神经元时IBS内脏痛动物模型的痛阈升高，抑制vlPAG内GABA能神经元时IBS内脏痛动物模型的痛阈降低；5）激活vlPAG脑区P2X3受体时IBS内脏痛动物模型的痛阈升高，电针可以调节vlPAG神经元上P2X3受体。研究结果证实vlPAG脑区内谷氨酸能和GABA能神经元均参与电针对IBS内脏痛动物模型的内脏痛觉调制，电针可能是通过调节vlPAG脑区神经元上P2X3受体改变神经元活动特性实现缓解IBS内脏痛动物模型的疼痛。