CB2受体参与电针抑制NLRP3炎性小体活化缓解紫杉醇化疗后神经病理痛机制

Mechanism on the involvement of CB2 receptor in inhibiting the activation of NLRP3 inflammasome by electroacupuncture on alleviating neuropathic pain after paclitaxel chemotherapy

目的:探讨CB2受体是否参与电针抑制NLRP3炎性小体活化从而缓解紫杉醇化疗后引起的神经病理痛。方法:将32只野生型(WT)和32只CB2R基因敲除(KO)小鼠分别随机分为溶媒对照组、紫杉醇组、电针组、假电针组,每组8只。各组小鼠在第1、3、5、7d腹腔注射紫杉醇(2mg/kg)诱导神经病理痛模型。在紫杉醇第1次注射后的第9天开始,针刺双侧"环跳"穴(GB30),每天进行1次电针治疗,共7d。电针治疗参数为1m A,疏密波,频率2Hz,时间为30min。测试小鼠机械痛阈值、坐骨神经组织中CB2R(只测野生型小鼠)、NLRP3、Caspase-1p20和IL-1βp17的蛋白表达水平。数据采用SPSS 23.0分析。结果:与各自的溶媒对照组比较,紫杉醇能显著下调WT和KO小鼠的机械痛阈(P<0.05),上调CB2R、NLRP3、Caspase-1p20和IL-1βp17的表达(P<0.05);与各自的紫杉醇组比较,WT电针组在治疗后第5天显著增加了机械痛阈(P<0.05)、进一步上调CB2R的表达(P<0.05),下调NLRP3、Caspase-1p20和IL-1βp17的表达(P<0.05),而WT假电针组则无此效果,KO电针组和假电针组对机械痛阈及检测的相关蛋白表达无显著影响。结论:电针通过激活外周CB2受体,抑制NLRP3炎性小体信号通路的激活,从而缓解紫杉醇化疗后神经病理痛。

Objective： To explore whether CB2 receptor was involved in inhibiting the activation of NLRP3 inflammatory cells by electroacupuncture and alleviating the neuropathic pain induced by paclitaxel chemotherapy or not. Methods： Thirty two CB2 receptor gene knockout（KO） mice and thirty two wild-type（WT） control mice with same nest were randomly divided into the control（CON） group, the paclitaxel（PAC） group, the electroacupuncture（PAC＋EA） group and the shame electroacupuncture（PAC＋shame EA） group, with eight mice in each group. Neuropathic pain model of mouse was established by intraperitoneal injection of paclitaxel（2 mg/kg） in the first, third, 5 th and 7 th days. On the 9 th day after the first injection of paclitaxel, the acupuncture on both sides of the Huantiao（GB30） was conducted once day, with a total of seven days. The electroacupuncture treatment related parameters were one milliampere（m A）, condensation-rarefaction wave, frequency two hertz（Hz）, and thirty minutes. The mechanical pain threshold, the protein expression levels of NLRP3, Caspase-1 p20, IL-1βp17 and CB2 R in the sciatic nerve tissue（only wild-type mice） of the mice were measured, and data were analyzed by SPSS 23.0. Results： Compared with the control group, paclitaxel could significantly down-regulated mechanical pain threshold（P〈0.05） and could significantly up-regulated the expression levels of CB2 R, NLRP3, Caspase-1 p20 and IL-1βp17 in both gene knockout mice and wild-type mice（P〈0.05）. At the fifth day after acupuncture treatment, compared with the PAC group, the expression level of CB2 R was significantly up-regulated（P〈0.05）, and the expression levels of NLRP3, Caspase-1 p20 and IL-1βp17 were significantly downregulated（P〈0.05）, and the pain threshold was significantly increased（P〈0.05）, in the PAC＋EA group. While there was no significant difference in the PCA＋shame EA group of WT mice. In terms of KO mice, there was no significant difference between the PAC＋EA group and the PAC＋shame EA group on the pain threshold and the related protein expression levels. Conclusion： Electroacupuncture can alleviate the neuropathic pain after paclitaxel chemotherapy by activating peripheral CB2 receptor and inhibiting the activation of NLRP3 inflammasome signal pathway.