内源性大麻素参与敏化穴位治疗腹泻型肠易激综合征的机制

The phenomenon of acupoint sensitization is the hotspot now. Acupoint sensitization means visceral diseases can generate the sensitization of sensation and function of some acupoints in body surface. The sensitized acupoints are not only the responsive points of the visceral disorders in the body surface, but also the stimulus points of acupuncture on specific points treating visceral disorders. The past research on this phenomenon just focused on the influence of the visceral diseases on the histochemistry characteristics of the sensitized acupoints. The effects and the mechanism of the sensitized acupoints modulating visceral function are not identified. This project will establish diarrhea-predominant irritable bowel syndrome (D-IBS) model. Take endocannabinoids as penetration point to explore the effect and the mechanisms of sensitized acupoints in regulating visceral motility and sensation based on D-IBS model by the methods of morphology,etholog, electrophysiology, and histochemistry. We will to clarify the material basis of functional sensitization of acupoints by linking the therapeutic effects of acupoint to the state of of acupoints, and to provide experimental evidence for guiding selection of acupoints in treating visceral diseases in clinical.

穴位敏化现象是近年研究的热点，是指在内脏疾病状态下，体表某些穴位可以发生感觉敏化和功能敏化。敏化穴位既是内脏疾病在体表的反应点，又是针灸特异性治疗内脏疾病的刺激点。目前对穴位敏化机制的研究还只是停留在内脏病变对体表敏化穴位组织化学特征的影响，而敏化穴位对病变内脏的调节效应及其机制还不清楚。本项目采用腹泻肠易激综合征（Diarrhea-predominant irritable bowel syndrome,D-IBS）内脏疾病模型，以内源性大麻素为切入点，采用形态学、行为学、电生理学、和组织化学方法研究体表敏化穴位对D-IBS大鼠内脏感觉和运动功能的调节效应及其机制，将穴位的治疗作用和穴位的状态联系起来，阐明穴位功能敏化的物质基础，为指导针灸治疗内脏疾病的临床选穴提供实验依据。

在内脏疾病状态下，体表穴位可出现神经源性炎症反应，这些发生炎性反应的敏化穴位既是内脏疾病在体表的反应点，又是针灸特异性治疗内脏疾病的刺激点。但是，目前研究多集中在观察敏化穴位组织化学特征的变化，而敏化穴位对病变内脏的调节效应及其机制还不清楚。本项目基于腹泻肠易激综合征（Diarrhea-predominant irritable bowel syndrome,D-IBS）内脏疾病模型，以内源性大麻素为切入点，研究体表敏化穴位对D-IBS大鼠内脏感觉和运动功能的调节效应及其机制。主要研究结果如下：(1) D-IBS大鼠体表神经源性炎症反应点主要分布在L4-6神经节段背部，与双侧“大肠俞”穴具有高度相关性；(2)D-IBS大鼠出现内脏痛觉过敏、腹泻、结肠运动增加表现，电针敏化穴位能显著改善D-IBS大鼠痛行为和腹泻症状，抑制结肠运动，但电针非敏化穴对D-IBS大鼠痛行为、腹泻症状、结肠运动没有影响；（3）在外周皮肤组织，D-IBS大鼠敏化穴区皮肤CB2R、SP表达上调，但是CB1R和IL-1β水平没有变化，电针敏化穴能进一步促进皮肤CB1R、CB2R表达，并降低IL-1β表达；（4）在结肠粘膜组织，D-IBS大鼠结肠CB2R、SP和IL-1β表达上调，但CB1R水平没有变化，电针敏化穴能进一步促进结肠CB1R、CB2R表达，并降低SP和IL-1β表达；（5）在脊髓背角水平，D-IBS大鼠L4-6节段CB1R表达降低，TRPV1表达上调，但CB2R水平没有变化，电针敏化穴位能促进CB1R表达，降低TRPV1表达；（6）腹腔注射CB2R受体拮抗剂（AM630）和CB1R受体拮抗剂（AM251）均能拮抗电针敏化穴对D-IBS大鼠的镇痛效应和抗腹泻行为，同时，注射AM630能逆转电针敏化穴对D-IBS大鼠结肠IL-1β的抑制效应，注射AM251能逆转电针敏化穴对D-IBS大鼠脊髓背角TRPV1的抑制效应。上述研究结果表明，大肠俞穴在D-IBS疾病状态下可以出现形态和功能敏化，其敏化机制与敏化穴区皮肤镇痛物质（CB1R、CB2R）和致痛物质（SP）表达失衡有关。在外周，电针敏化穴位对D-IBS大鼠的调节效应与促进结肠CB1R、CB2R表达，抑制SP和IL-1β表达有关。在脊髓水平，电针敏化穴位对D-IBS大鼠的调节效应与促进CR1R表达，抑制TRPV1表达有关。