电针刺激足三里与IBS大鼠内脏痛觉信息在DRG交互机制研究

Irritable bowel syndrome（IBS）is a functional gastrointestinal disorder characterized by persistent pain and organ hypersensitivity in the absence of demonstrable gross structural or biochemical abnormalities.The life quality of patients is seriously affected. Chronic visceral hypersensitivity is the main pathophysiological characteristics of irritable bowel syndrome.Different levels gut–brain axis has been shown to be involved in this disease. there is peripheral sensitization and central sensitization in two states.As an important part of traditional Chinese medicine, acupuncture has 5000-year history in the treatment of IBS visceral pain and diarrhea and has been used extensively in clinics. To the current period，It has not been reported about the Neurobiological mechanisms of electricacupuncture in relieving visceral pain of peripheral sensitization. Combined with traditional Chinese medicine Meridian-Viscera Correlation theory, we mark the spatial distribution of visceral and somatic (acupoints and viscera)sensory neurons in dorsal root ganglion（DRG） using Neuron Retrograde Labeling Techniques.Then reveal whether there are functional links between the two types of neurons? What is the material basis of the functional relationship between the two types of neurons?Exploring the Biological Mechanism of electroacupuncture to regulate information interaction between Meridian and visceral sensory neuron of rat with visceral hypersensitivity using neuroelectrophysiology and molecular biology techniques.Electroacupuncture activates Aβ fiber low threshold mechanical receptor(LTMR),promoting release of ATP from large-diameter DRG neurons and modulates pain by P2X7→P2Y1→P2X3 inhibitory pathway.We propose the "Neuron-Glia-Neuron" functional unit of information crosstalk. we put forward the "functional unit Neuron-Glia-Neuron" this information interaction, around the regulatory role this unit of Electroacupuncture on visceral pain of peripheral sensitization to study the regulation effect of electroacupuncture at Zusanli on peripheral sensitization of visceral pain around this functional unit.

肠易激综合征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。慢性内脏高敏感是肠易激综合征主要病理生理特征。脑肠轴不同水平均有参与，存在外周敏化和中枢敏化两种状态，针灸治疗腹痛、腹泻已有几千年历史和丰富的临床经验。尚未见关于针灸缓解内脏痛外周敏化的神经电生理机制报道。结合中医经穴脏腑相关理论，我们采用神经逆行示踪标记躯体-内脏（经穴与脏腑）两类初级感觉神经元在DRG空间分布，然后揭示两类神经元是否存在功能联系？两类神经元功能联系的物质基础是什么？用神经电生理与分子生物学技术探索电针调节经穴与脏腑感觉神经元信息交互的生物学机制。电针机械刺激激活Aβ纤维低阈值机械感受器，促进大直径DRG神经元释放ATP，作用P2X7→P2Y1→P2X3抑制途径来发挥痛觉调制，我们提出“Neuron-Glia-Neuron”这一信息交互的功能单位，围绕这一功能单位研究电针足三里对内脏痛外周敏化的调节作用。

慢性内脏高敏感是肠易激综合征主要病理生理特征，存在外周敏化和中枢敏化两种状态，针灸治疗腹痛、腹泻已有几千年历史和丰富的临床经验。本研究旨在探讨DRG中P2X7和P2Y1受体在电针足三里、三阴交缓解内脏痛敏中的作用机制，以促进结合中医经穴脏腑相关理论的揭示。研究采用TNBS灌肠诱导IBS大鼠内脏痛模型，给予双侧足三里、三阴交穴电针刺激（1mA，2Hz，0.1ms），15min/次，1次/日，共1周。运用形态学、神经药理学、行为学、神经逆行示踪标、电生理学、分子生物学等方法，探索DRG中躯体和内脏相关感觉神经元的P2X7和P2Y1受体介导电针缓解内脏痛敏的神经分子生物学机制。我们研究揭示了电针能够明显抑制由TNBS诱导的IBS大鼠结肠内脏高敏感性；DRG中结肠相关感觉神经元主要分布在T12-L2和L6-S2节段；电针刺激能够抑制DRG中结肠相关感觉神经元的兴奋性（降低静息膜电位、上调神经元的基强度、抑制敏化的神经元动作电位数量），胶质细胞可能参与了电针调节神经元电生理学特性；结肠相关DRG中胶质细胞的P2X7蛋白表达上调，P2X7R在IBS内脏高敏感过程中发挥了促进作用，电针能够通过抑制P2X7蛋白而发挥镇痛效应。P2X7的痛觉调节是通过对P2X3受体功能的调节实现的，P2Y1在TNBS诱导的IBS内脏痛过程中发挥了痛觉抑制作用，P2Y1介导了电针缓解TNBS诱导的IBS内脏高敏感过程。电针能够调节TNBS诱导的IBS大鼠DRG中P2Y1蛋白表达。P2Y1能够通过调节神经元中与伤害性信息感知的P2X3受体来实现对内脏痛觉的调制，P2X7位于电针对P2Y1发挥上调作用的上游，且这一过程中有缝隙连接蛋白通道作为媒介发挥作用；另外，电针可以抑制内脏高敏感大鼠脊髓背角的sEPSC和钙电流增加，即对脊髓敏化同样具有抑制作用。我们推测，DRG中“Neuron-Glia-Neuron”作为信息交互的功能单位，其中的“P2X7→P2Y1→P2X3”抑制途径介导了电针抑制TNBS诱导IBS内脏痛大鼠的外周敏化，为中医经脉脏腑相关理论的揭示提供了证据支持。