脊髓小胶质细胞α7nAChR在瑞芬太尼诱导痛觉过敏中的作用及机制的研究

Remifentanil induced hyperalgesia limits its clinical applications and the mechanism of this hyperalgesia has not be clarified yet. The spinal cord microglial plays an important role in the occurrence and maintace of hyperalgesia. Our previous findings in remifentanil-induced hyperalgesia rat models certified the spinal microglia are involved in this process. Recent research indicated that the modulation of α7 acetylcholine receptor (α7nAChR) on microglia play an important role in the process of hyperalgesia. This project intends to investigate the mechanism of remifentanil induced hyperalgesia by evaluating α7nAChR-microglia in spinal cord。The effect of the α7nAChR allosteric activators, agonists, antagonists on microglia ERK/JNK/P38 phosphate and the inflammatory product were also evaluated in remifentanil induced hyperalgesia models. The implementation of this research would provide fundamental theory for the rational use of remifentanil in clinical and novel ideas for the treatment of remifentanil-indued hyperalgesia.

瑞芬太尼所致痛觉过敏限制了其临床应用，且迄今仍未阐明其机制。脊髓的小胶质细胞在疼痛的发生及维持中发挥重要。我们的前期研究发现在瑞芬太尼所致的痛觉过敏中脊髓小胶质细胞参与到这一过程中。文献表明α7乙酰胆碱受体（α7nAChR）介导的对中枢小胶质细胞的调制在疼痛过程中发挥重要作用。本项目拟通过评价瑞芬太尼痛觉过敏模型中脊髓背角小胶质细胞及α7nAChR变化，以及α7nAChR变构激活剂、激动剂、拮抗剂对小胶质细胞ERK/JNK/P38磷酸化及炎性产物的影响，明晰小胶质细胞参与瑞芬太尼所致痛觉过敏痛的机制，为治疗临床治疗瑞芬太尼所致痛觉过敏提供新的思路。

瑞芬太尼诱导的痛觉过敏临床上加重患者不适，影响术后恢复，限制其临床应用。本研究在大鼠瑞芬太尼诱导痛觉过敏的模型上，评价脊髓背角α7烟碱型乙酰胆碱受体(α7nAChRs)及相关信号通路对瑞芬太尼诱导的术后痛觉过敏的作用。为临床合理使用瑞芬太尼和防治其诱导的术后痛觉过敏提供理论依据。我们的研究显示：1、在大鼠行切口手术同时，皮下泵注瑞芬太尼80 μg/kg，持续30min可以诱发术后机械痛敏和热痛敏，上调脊髓水平星形胶质细胞和小胶质细胞水平以及炎性指标相关因子如TNF-α, IL-6，促进脊髓背角NR2B亚基磷酸化，提示在瑞芬太尼诱发的痛觉过敏中多种因素发挥作用。2、鞘内注射α7nAChRs激动剂（PHA-543613）及Ⅱ型变构激活剂（PNU-120596）可剂量依赖性抑制瑞芬太尼痛觉过敏，α7nAChRs激动剂及Ⅱ型PAMs可减低瑞芬太尼痛觉过敏中脊髓小胶质细胞、星形胶质细胞及促炎性产物，但Ⅰ型变构激活剂（NS-1738）则无此效应；3、α7nAChRs激动剂及Ⅱ型PAMs可降低瑞芬太尼痛觉过敏中脊髓络氨酸磷酸化NR2B（p-NR2B）的水平；4、α7nAChRs激动剂及Ⅱ型PAMs可缓解瑞芬太尼痛觉过敏中脊髓BDNF的增加。5、PHA-543613和PNU-120596的镇痛作用可被α7nAChRs拮抗剂MLA阻断；6、亚镇痛剂量的α7nAChRs激动剂及Ⅱ型变构激活剂联合注射亦可抑制瑞芬太尼痛觉过敏。7、术前鞘内注射α7nAChRs激动剂及Ⅱ型PAMs PNU-120596 可通过抑制BDNF/trkB-KCC2信号通路，缩短瑞芬太尼所致通过过敏的时程。8、鞘内注射JWH015（CB2受体激动剂）可以通过下调脊髓背角NR2B磷酸化，抑制胶质细胞活化及抑制炎症因子，缓解瑞芬太尼诱导的术后痛觉过敏。