IL-33/ST2通路参与急性痛风关节炎疼痛的神经免疫机制及电针干预作用研究

Acute gout arthritis (AGA) can induce severe pain in the joint and surrounding tissues, which usually makes the patient hard to endure and severely affects his/her life quality. Acupuncture effectively alleviates AGA pain in clinic, while exerting no obvious side effects. However, the mechanisms underlying its analgesic effect on AGA-induced pain is not fully understood yet. In our previous studies, we identified that the expression of IL-33/ST2 signaling pathway is significantly up-regulated in the gouty joints of mice by means of RNA-Seq technique. In addition, ST2 knockout significantly reduced the nocifensive behaviors of AGA model mice. Our recent study demonstrated that IL-33/ST2 pathway plays a pivotal role in mediating peripheral sensory neuron excitability. Therefore, this project aims to investigate IL-33/ST2-induced sensory neuron excitability and IL-33/ST2-induced neutrophil infiltration in inflammatory joints by means of immune blot/fluorescence, calcium imaging, patch clamp, retrograde labeling, behavioral assay and transgenic mice, etc., all of which will help to reveal the neuroimmune mechanisms of IL-33/ST2 pathway involved in AGA pain. Next,the project aims to explore the interventions of electroacupuncture on IL-33/ST2 pathway. In all, this project will unravel the novel molecular mechanisms involved in AGA-induced pain and provide important theory to support the treatment of AGA with acupuncture. This project may help to further promote the clinical practice of acupuncture in treating AGA-induced pain as a “green therapy”.

急性痛风性关节炎可造成关节部位剧痛，患者疼痛难耐，严重影响生活质量，而抗痛风药副作用明显。针刺在临床上可有效缓解急性痛风性关节炎疼痛，且无明显副作用，但其镇痛机制尚未明确。前期研究中，申请人利用RNA-Seq技术发现IL-33/ST2通路在小鼠痛风关节表达增高，且敲除ST2可缓解痛风小鼠痛行为。申请人近期一项研究发现IL-33/ST2通路在介导外周感觉神经元兴奋性方面有重要作用。本项目拟在前期研究基础上，以IL-33/ST2通路激动感觉神经元和引发炎症部位中性粒细胞浸润为切入点，整合免疫学、细胞内钙成像、膜片钳、逆行标记、行为学和转基因动物等手段，探讨该通路参与急性痛风性关节炎疼痛的神经免疫机制，并探讨电针对该通路的干预作用。该研究将揭示急性痛风性关节炎疼痛产生的崭新机制，并为针刺治疗急性痛风性关节炎提供重要理论依据，有助于推动其作为“绿色疗法”用于急性痛风性关节炎疼痛的临床治疗。

急、慢性痛可严重影响患者生活质量，并造成身心负担。针刺在临床上可有效缓解多种急慢性痛，然而其确切机制尚不完全清晰。近期一些研究发现针刺可干预和调节中枢或外周与痛觉或炎症相关信号通路，发挥镇痛效果。因此本课题以急性痛风性关节炎、I型复杂性区域性疼痛综合征（CRPS-I）和化疗药物紫杉醇诱发外周神经病理痛（CIPN）动物模型为切入，利用神经免疫学、神经电生理、细胞内钙成像、药理学和动物行为学等技术手段，研究电针对神经免疫及炎症信号通路的干预作用，阐明电针镇痛效应机制。本课题主要发现如下：①成功建立了动物急性痛风性关节炎模型，并对其疼痛机制进行探讨，发现IL-33/ST2信号通路可介导炎症关节中性粒细胞浸润，释放氧化应激产物。氧化应激产物一方面激动痛敏感TRPA1通道，另一方面激活NLRP3炎性小体，从而在介导急性痛风性关节炎疼痛和炎症方面发挥作用；在此基础上，探讨了电针对相关炎症痛路、炎性细胞浸润、氧化应激发生及痛敏感离子通道过表达的干预。②筛选出电针干预CRPS-I模型大鼠疼痛的优势频率，发现电针可减少脊髓背角（SCDH）中CXCL12/CXCR4及NLRP3炎性小体过表达，抑制SCDH中神经元、星形胶质细胞和小胶质细胞过度激活和磷酸化ERK过表达。③发现低频电针可有效缓解CIPN模型大鼠疼痛，并抑制背跟神经节（DRG）中TLR4、MyD88、TRPV1过表达及TRPV1通道功能活性增强。发现CIPN模型大鼠SCDH中星形胶质细胞和小胶质细胞出现过度活化，而电针可干预其过度活化。电针镇痛效果可被TRPV1通道阻断剂模拟，并被TRPV1通道激动剂逆转。上述研究发现了电针干预急性痛风性关节炎、CRPS-I以及CIPN的崭新机制，从而有助于推动电针作为一种绿色疗法，应用于上述急、慢性痛的临床治疗。