针刺调控痛觉中枢敏化的机制研究

Acupuncture analgesia is not only the treasure of the Traditional Chinese Medicine, but also one of the important reseach areas in neuroscience and surgery. Studies for acupuncture analgesia mainly focus on its regulation of physiologic pain. However,the central regulating mechanism by which acupuncture relieves pathologic pain has not been investigated yet.Numerous studies have showed that the activation of glial cells and the release of their cytokines have important roles in the initiation and maintenaince of the central sensitization which is caused by the pathologic pain. In the present program, pathologic pain of the goats is induced with the chronic constriction injury of the sciatic nerve. The goats are stimulated with acupuncture applied to Zusanli points bilaterally for 30 min at day 8 after the surgery, and thereafter one time every three days, for total nine times. The pain thresholds of mechanical allodynia and heat hyperalgesia are measured, respectively, immediately after every acupuncture. Six goats, randomly taken from each group after the pain threshold measurement at day 8, 14, 20, 26 and 32, respectively, are euthanized. The lumbar enlargement of the spinal cord is taken out immediately. The dynamic expression levels of neural activators,molecules symboling for glial cell activation, and glial cell-derived inflammatory cytokines and chemokines are detected.the correlations of these active substances with pain thresholds are analyzed. Then antagonists or agonists to the significantly changed active substances are microinjected into the subarachnoid space in order to verify the roles of these active substances in the acupuncture modification of the central sensitization. This project is conducive to clarify the central mechanisms by which acupuncture relieves the pathologic pain, to promote the development of the neuroscience and the application of acupuncture analgesia in the veterinary clinical practice.

针刺镇痛是传统中医学的瑰宝，是神经科学和外科学领域的重要研究方向之一。现有针刺镇痛研究主要集中在其调控生理性疼痛方面，但针刺调控病理性疼痛的中枢机制缺乏研究。研究表明胶质细胞的活化及其细胞因子的释放对病理性疼痛中枢敏化的产生和维持起重要作用。本项目利用山羊神经病理性疼痛模型，于术后第8天针刺双侧“足三里”穴30min，以后每3天1次，共9次。每次电针后检测机械痛阈和热痛阈，评价针刺调控山羊病理性疼痛的效果；分别于造模手术后第8、14、20、26和32天从各试验组中随机选取6只山羊安乐死，检测脊髓神经活性物质、胶质细胞活性标志物以及胶质细胞源促炎细胞因子和趋化因子的表达水平，分析这些活性物质与痛阈变化的相关性。脊髓鞘内微注射相关活性物质激动剂或拮抗剂，进一步证实其在针刺调控痛觉中枢敏化中的作用。该研究有助于揭示针刺治疗病理性疼痛的中枢机制，促进神经科学的发展和针刺镇痛在兽医临床中的应用。

本项目采用高通量测序技术，发现与多种针刺镇痛调节相关生物活性物质存在差异表达。在此基础上，我们研究了针刺诱导中枢核团（区）阿片肽原（甲脑啡肽前原 阿黑皮素原 前强啡肽原）、抗阿片肽（八肽胆囊收缩素和孤啡肽）及其相应受体变化的时空规律；采用药物学（激动剂和拮抗剂）、免疫学（抗体的拮抗和免疫组化）或分子生物学（基因沉默、过表达载体和荧光定量PCR）手段，检测针刺诱导中枢胸腺素β4、蛋白酶激活受体2、降钙素基因相关肽、p38 MAPK、JAK2-STAT3等的变化，分析其与痛阈变化的相关性。结果发现中枢阿片肽与抗阿片肽水平的倾斜决定针刺镇痛耐受；胸腺素β4通过影响阿片肽和抗阿片肽水平参与针刺耐受的形成；针刺通过干预脊髓蛋白酶激活受体2和降钙素基因相关肽释放缓解内脏超敏，还通过抑制突触结合蛋白1缓解神经病理性疼痛；针刺通过抑制中枢痛觉调制通路神经元中信号分子p38 MAPK、JAK2-STAT3等缓解病理性疼痛。这些研究初步阐明了针刺调控痛觉中枢敏化的分子机制，为疼痛的药物干预提供了新的分子靶标，同时也有助于推动针刺技术在临床上的应用，弘扬我国的传统医学。本项目培养博士研究生3名和硕士研究生4名，发表SCI研究性论文5篇，申请国家发明专利1项。