电针不同穴位对颈部切口痛大鼠颈段背根节内卫星胶质细胞活动的影响

摘要

Objective To observe the effect of electroacupuncture (EA) stimulation of "Futu"(LI 18), etc.on activities of satellite glial cells (SGCs) in the dorsal root ganglia (DRG) in rats with neck-incision pain so as to explore its mechanism underlying reduction of post-surgical pain of thyroidectomy.Methods Male SD rats were randomly divided into control, model, EA-Futu (LI 18), EA-Hegu (LI 4)-Neiguan (PC 6), and EA-Zusanli (ST 36)-Yanglingquan (GB 34) groups, with 20 rats in each group.The neck-incision pain model was established by making a longitudinal incision and repeated mechanical stimulation.In the EA-LI 18, EA-LI 4-PC 6 and EA-ST 36-GB 34 groups, EA stimulation was administrated for 30 min, once a day,continuously for 3 days.The thermal pain threshold (PT) of the neck-incision region was detected.The immunoactivity of glial fibrillary acidic protein (GFAP,a specific marker for SGCs) and connexin 43 (Cx 43) of DRGs (C 2-C 6) was determined by fluorescent immunohistochemistry.The expression levels of GFAP, IL-1 β, IL-6, and TNF-α mRNAs were determined by quantitative Real-time PCR, and the contents of IL-1 β,IL-6,TNF-α assayed by enzyme linked immunosorbent assay (ELISA) and the expression of Cx 43 protein was detected by Western blot.Results After EA intervention at LI 18 and LI 4-PC 6 (but not ST 36-GB 34), neck incision-induced reduction of the thermal PT was obviously prolonged in comparison with the model group (P<0.05),suggesting a pain relief.The expression levels of GFAP, IL-1 β, IL-6 and TNF-α mRNAs and Cx 43 protein, and the contents of IL-1 β, IL-6 and TNF-α in C 2-C 6 DRGs were all significantly up-regulated in the model group relevant to those of the control group (P<0.05).Following EA, modeling induced dramatic increase of expression of GFAP , IL-1 β, IL-6 and TNF-α mRNAs and Cx 43 protein in both EA-LI 18 and EA-LI 4-PC 6 groups, and the contents of IL-1 β and TNF-α in the EA-LI 18 group, IL-6 in the EA-LI 4-PC 6 group was considerably down-regulated (P<0.05).In comparison with the model group, no significant changes were found in all the abovementioned indexes of EA-ST 36-GB 34 group except the down-regulated IL-1 β and TNF-α mRNAs, in the contents of IL-1 β and TNF-α of the EA-LI 4-PC 6 group, and in the IL-6 content of the EA-LI 18 group (P>0.05).Conclusion EA stimulation of LI 18 and LI 4-PC 6 can significantly suppress pain reaction of neck incision in the rat, which is closely associated with its effects in down-regulating the activity of SGCs, decreasing the release of pro-inflammatory cytokines and in weakening the expression of Cx 43 in the cervical DRGs.%目的:通过观察电针对甲状腺区切口痛大鼠颈背根神经节(DRG)内卫星胶质细胞(SGCs)活性的影响,探讨针刺缓解术后痛或针刺镇痛行甲状腺手术的机制.方法:SD大鼠随机分为正常组、模型组、扶突组、合谷-内关组、足三里-阳陵泉组,每组20只.除正常组外,沿大鼠颈正中线做一纵行切口并反复分离刺激,制作甲状腺区切口痛模型.各治疗组分别电针双侧"扶突""合谷-内关""足三里-阳陵泉"穴,1次/d,连续3 d.检测大鼠切口部位热痛阈;用免疫荧光、Real-time PCR、ELISA和蛋白免疫印迹法分别检测大鼠脊髓颈(C)2-C 6 DRGs内SGCs标记物胶质纤维酸性蛋白(GFAP)、connexin 43(Cx 43)免疫荧光强度和白细胞介素-1 β(IL-1 β)、肿瘤坏死因子-α(TNF-α)、IL-6 mRNA和蛋白表达量以及Cx 43蛋白表达量.结果:模型组大鼠颈部的热痛阈较正常组明显缩短(P<0.05);扶突组和合谷-内关组大鼠热痛阈均较模型组和足三里-阳陵泉组显著延长(P<0.05).DRGs内GFAP免疫荧光强度及mRNA表达水平与IL-1 β、TNF-α、IL-6 mRNA和蛋白表达量及Cx 43免疫荧光强度与蛋白表达量在模型组均明显上调(P<0.05);与模型组比较, 电针双侧"扶突""合谷-内关"穴后GFAP免疫荧光强度及mRNA表达水平与IL-1 β、TNF-α、IL-6 mRNA表达水平和Cx 43免疫荧光强度与蛋白表达量,扶突组IL-1 β、TNF-α与合谷-内关组 IL-6蛋白表达量均明显下调(P<0.05),足三里-阳陵泉组除IL-1 β、TNF-α mRNA外,多数指标变化不明显(P>0.05).结论:电针"扶突""合谷-内关"穴可缓解大鼠颈部切口痛,该作用可能与其下调C 2-C 6 DRGs内SGCs活性,减少促炎细胞因子的释放,减弱SGCs间信息交流密切相关.