Effect of moxibustion on N-methyl-D-aspartate receptor subtype 2B expression in hippocampus of rheumatoid arthritis model rats

艾灸对类风湿性关节炎模型大鼠海马N-甲基-D-天门冬氨酸受体2B亚基表达的影响

Objective:To observe the effect of moxibustion on the expression of N-methyl-D-aspartic acid(NMDA)receptor subtype 2B(NR2B)in the hippocampus of rheumatoid arthritis(RA)rats,and to explore the analgesic mechanisms of moxibustion in RA treatment.Methods:Sixty male Sprague-Dawley rats were randomly divided into a normal group,a model group,a moxibustion group,a moxibustion+NMDA receptor antagonist(AP-5)group,and a moxibustion+NMDA receptor agonist(NMDA)group,with 12 rats in each group.Except for the normal group,rats in the other four groups were treated with complete Freund's adjuvant in a windy,cold,and damp environment to replicate RA models.Rats in the moxibustion group received suspended moxibustion with moxa sticks at Shenshu(BL23)and Zusanli(ST36),and the two points were used alternately.After intraperitoneal injection of AP-5 or NMDA,rats in the moxibustion+AP-5 group and the moxibustion+NMDA group received the same moxibustion intervention as in the moxibustion group,once a day for 15 d.The thermal withdrawal latency(TWL)of rats in each group was detected before and after modeling and after the 15-day intervention.After the 15-day intervention,hematoxylin-eosin staining was performed to observe the pathological changes in knee joints.The real-time fluorescence quantitative polymerase chain reaction method was used to detect the mRNA expression of NR2B in the hippocampus;Western blotting assay was used to detect the protein and the phosphorylated protein expression of hippocampal NR2B.Results:The synovial tissue was proliferated,the synovial lining was significantly thickened,the pannus was formed,and the cartilage and bone tissues were significantly damaged in the model group.After intervention,the pathological morphology of the knee joints in the moxibustion group,the moxibustion+AP-5 group,and the moxibustion+NMDA group was significantly improved,and the improvement in the moxibustion+AP-5 group was more notable than that in the moxibustion+NMDA group.Compared with the normal group,the TWL was significantly decreased(P<0.01),and the mRNA,protein,and phosphorylated protein expression levels of hippocampal NR2B were significantly increased in the model group(P<0.01).Compared with the model group,the TWL of each intervention group was significantly increased(P<0.01 or P<0.05),and the mRNA,protein,and phosphorylated protein expression levels of hippocampal NR2B were significantly decreased(P<0.01).Compared with the moxibustion group,the TWL was significantly increased(P<0.01),and the mRNA,protein,and phosphorylated protein expression levels of hippocampal NR2B were significantly decreased in the moxibustion+AP-5 group(P<0.01);the TWL was significantly decreased(P<0.01),and the mRNA,protein,and phosphorylated protein expression levels of hippocampal NR2B were significantly increased in the moxibustion+NMDA group(P<0.01).Conclusion:Moxibustion reduces hyperalgesia in RA inflammatory rats.The analgesic effect may be related to the decrease in the expression and phosphorylation levels of NR2B in the hippocampus.

目的:观察艾灸对类风湿性关节炎(RA)大鼠海马N-甲基-D-天门冬氨酸(NMDA)受体2B亚基(NR2B)表达的影响,探讨艾灸治疗RA的镇痛作用机制.方法:将60只雄性Sprague-Dawley大鼠随机分为正常组、模型组、艾灸组、艾灸+NMDA受体拮抗剂(AP-5)组和艾灸+NMDA受体激动剂(NMDA)组,每组12只.除正常组外,其余四组采用风、寒、湿环境因素结合完全弗氏佐剂复制RA模型.艾灸组接受艾条悬灸肾俞及足三里,两穴交替使用;艾灸+AP-5组和艾灸+NMDA组分别给予腹腔注射AP-5、NMDA后接受与艾灸组相同的艾灸干预.每日1次,共干预15 d.分别于造模前后和干预15 d后检测各组大鼠热缩足反射潜伏期(TWL);干预15 d后采用苏木素-伊红染色法观察膝关节病理形态学变化;实时荧光定量聚合酶链式反应法检测海马NR2B mRNA的表达,免疫印迹法检测海马NR2B蛋白、磷酸化NR2B的表达.结果:模型组大鼠滑膜组织增生,滑膜衬里层明显增厚,有血管翳形成,软骨、骨组织破坏明显.干预后,艾灸组、艾灸+AP-5组、艾灸+NMDA组大鼠膝关节病理形态学明显改善,同时艾灸+AP-5组的改善情况优于艾灸+NMDA组.与正常组相比,模型组大鼠TWL显著下降(P<0.01),海马NR2B mRNA及蛋白的表达和磷酸化水平显著增加(P<0.01).与模型组相比,各干预组TWL显著提高(P<0.01或P<0.05),海马NR2B mRNA及蛋白的表达和磷酸化水平显著下降(P<0.01).与艾灸组相比,艾灸+AP-5组TWL显著提高(P<0.01),海马NR2B mRNA及蛋白的表达和磷酸化水平显著下降(P<0.01);艾灸+NMDA组TWL显著下降(P<0.01),海马NR2B mRNA及蛋白的表达和磷酸化水平显著增加(P<0.01).结论:艾灸可以减轻RA炎症性大鼠痛敏反应,其镇痛作用可能与艾灸能够降低海马NR2B表达及磷酸化水平有关.