Abstract:
Background: Recent studies have demonstrated that activated microglia were involved in the pathogenesis of central sensitization characterized by cutaneous allodynia in migraine. Activation of microglia is accompanied by increased expression of its receptors and release of inflammatory mediators. Acupuncture and its developed electroacupuncture (EA) have been recommended as an alternative therapy for migraine and are widely used for relieving migraine-associated pain. However, it remains rare studies that show whether EA exerts anti-migraine effects via inhibiting microglial activation related to a release of microglial receptors and the inflammatory pathway. Therefore, this study aimed to investigate EA\' ability to ameliorate central sensitization via modulation of microglial activation, microglial receptor, and inflammatory response using a rat model of migraine induced by repeated epidural chemical stimulation. Methods: In the present study, a rat model of migraine was established by epidural repeated inflammatory soup (IS) stimulation and treated with EA at Fengchi (GB20) and Yanglingquan (GB34) and acupuncture at sham-acupoints. Pain hypersensitivity was further determined by measuring the mechanical withdrawal threshold using the von-Frey filament. The changes in c-Fos and ionized calcium binding adaptor molecule 1 (Ibal-1) labeled microglia in the trigeminal nucleus caudalis (TNC) were examined by immunflurescence to assess the central sensitization and whether accompanied with microglia activation. In addition, the expression of Ibal-1, microglial purinoceptor P2X4, and its associated inflammatory signaling pathway mediators, including interleukin (IL)-1β, NOD-like receptor protein 3 (NLRP3), and Caspase-1 in the TNC were investigated by western blot and real-time polymerase chain reaction analysis. Results: Allodynia increased of c-Fos, and activated microglia were observed after repeated IS stimulation. EA alleviated the decrease in mechanical withdrawal thresholds, reduced the activation of c-Fos and microglia labeled with Ibal-1, downregulated the level of microglial purinoceptor P2X4, and limited the inflammatory response (NLRP3/Caspase-1/IL-1β signaling pathway) in the TNC of migraine rat model. Conclusions: Our results indicate that the anti-hyperalgesia effects of EA ameliorate central sensitization in IS-induced migraine by regulating microglial activation related to P2X4R and NLRP3/IL-1β inflammatory pathway.
摘要:
背景:最近的研究表明,活化的小胶质细胞参与了以偏头痛皮肤异常性疼痛为特征的中枢致敏的发病机制。小胶质细胞的活化伴随着其受体表达的增加和炎症介质的释放。针灸及其开发的电针(EA)已被推荐为偏头痛的替代疗法,并被广泛用于缓解偏头痛相关的疼痛。然而,目前还很少有研究表明EA是否通过抑制与小胶质细胞受体释放和炎症途径相关的小胶质细胞活化来发挥抗偏头痛作用.因此,本研究旨在研究EA通过调节小胶质细胞活化改善中枢致敏的能力,小胶质细胞受体,使用反复硬膜外化学刺激引起的偏头痛大鼠模型和炎症反应。
方法:在本研究中,通过硬膜外反复炎症汤(IS)刺激建立大鼠偏头痛模型,并在风池(GB20)和阳陵泉(GB34)上进行EA和假穴针刺治疗。通过使用von-Frey细丝测量机械戒断阈值来进一步确定疼痛超敏性。通过免疫荧光检查三叉神经尾核(TNC)中c-Fos和离子化钙结合衔接分子1(Ibal-1)标记的小胶质细胞的变化,以评估中枢致敏作用以及是否伴有小胶质细胞活化。此外,Ibal-1、小胶质细胞受体P2X4及其相关炎症信号通路介质的表达,包括白细胞介素(IL)-1β,NOD样受体蛋白3(NLRP3),通过蛋白质印迹和实时聚合酶链反应分析研究了TNC中的Caspase-1。
结果:c-Fos异常性疼痛增加,重复IS刺激后观察到活化的小胶质细胞。EA缓解了机械退出阈值的降低,在偏头痛大鼠模型的TNC中,c-Fos和Ibal-1标记的小胶质细胞的活化降低,小胶质细胞受体P2X4的水平下调,并限制炎症反应(NLRP3/Caspase-1/IL-1β信号通路)。
结论:我们的结果表明,EA的抗痛觉过敏作用通过调节与P2X4R和NLRP3/IL-1β炎症通路相关的小胶质细胞活化来改善IS诱导的偏头痛的中枢敏化。