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

Effects of Electroacupuncture on Activities of Satellite Glial Cells of Dorsal Root Ganglia in Rats with Neck Incision Pain

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3d。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 6DRGs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-1β(IL-1β)、肿瘤坏死因子-α(TNF-α)、IL-6mRNA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-1β、TNF-α、IL-6mRNA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-1β、TNF-α、IL-6mRNA表达水平和Cx 43免疫荧光强度与蛋白表达量,扶突组IL-1β、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-1β、TNF-αmRNA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 6DRGs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。

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 6and EA-ST 36-GB 34 groups,EA stimulation was administrated for 30 min,once a day,continuously for 3days.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-1β,IL-6,and TNF-αmRNAs were determined by quantitative Real-time PCR,and the contents of IL-1β,IL-6,TNF-αassayed 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 incisioninduced reduction of the thermal PT was obviously prolonged in comparison with the model group（P〈0.05）,suggesting apain relief.The expression levels of GFAP,IL-1β,IL-6and TNF-αmRNAs and Cx 43 protein,and the contents of IL-1β,IL-6and TNF-αin C 2-C 6DRGs 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-1β,IL-6and TNF-αmRNAs and Cx 43 protein in both EA-LI 18 and EA-LI 4-PC 6groups,and the contents of IL-1βand TNF-αin the EA-LI 18 group,IL-6in the EA-LI 4-PC 6group 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-1βand TNF-αmRNAs,in the contents of IL-1βand TNF-αof the EA-LI 4-PC 6group,and in the IL-6content of the EA-LI 18group（P〈0.05）.Conclusion EA stimulation of LI 18 and LI 4-PC 6can 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.