电针对神经痛和负性情绪大鼠杏仁核内痛感觉和情绪成分相关促皮质激素释放因子受体等基因表达的影响

目的:观察电针对慢性痛大鼠杏仁核内痛感觉和情绪相关促皮质激素释放因子(CRF)受体等基因表达的影响,探讨电针镇痛的作用机制。方法:Wistar大鼠分为2批,第1批随机分为正常组、慢性压迫性损伤(chronic constrictive injury,CCI)模型组、CCI+电针组,第2批随机分为正常组、CCI+负性情绪(negative affection,NA)模型组、CCI+NA+电针组,每组6只。坐骨神经结扎术造成CCI神经痛模型,手持通电的针灸针反复刺激CCI大鼠足底造成动物NA模型。电针双侧"足三里"-"阳陵泉"穴,每日1次,共7d。测定大鼠双足底缩腿热反应潜伏期(PWL),计算健侧与患侧的差值(PWLD);用荧光定量RT-PCR技术检测杏仁核CRF受体亚型CRF-1R、CRF-2R,谷氨酸及N-甲基-D-天冬氨酸(NMDA)受体亚型NR 2A、NR 2B,γ-氨基丁酸(GABA)受体亚型GABAaR、GABAcR基因的表达。结果:与正常组比,CCI、CCI+NA模型组PWLD均显著增加(P0.05);分别与两模型组比,电针7d后PWLD显著下降(P0.05),镇痛效应明显。PCR结果显示,与正常组比,CCI模型组CRF-1R、CRF-2R、NR 2A、NR 2B基因表达量均显著增加(P0.01,P0.001),GABAaR及GABAcR基因表达变化不明显(P0.05),而CCI+NA模型组6个指标基因表达量均显著降低(P0.05,P0.001,P0.01);与CCI模型组比,CCI+电针组CRF-2R、NR2A、NR 2B基因表达量显著降低(P0.01,P0.001);与CCI+NA模型组比,CCI+NA+电针组除NR2A外,其它基因表达水平均显著增加(P0.01)。结论:重复电针可减轻慢性痛和负性情绪大鼠的疼痛反应,其效应可能与其降低神经痛大鼠杏仁核CRF-2R、NR 2A、NR 2B基因表达,增加负性情绪大鼠杏仁核CRF-1R、CRF-2R、NR 2B、GABAaR、GABAcR基因的表达,进而影响疼痛的情绪和感觉成分有关。

Effect of Electroacupuncture Intervention on Expression of Pain Sensory and Affection Processing-related Corticotropin-releasing Factor Receptor mRNA,etc.in the Amygdala in Neuropathic Pain and Negative Affection Rats

Objective To observe the effect of electroacupuncture(EA)stimulation of"Zusanli"(ST 36)-"Yanglingquan"(GB 34)on expression of pain sensory and affection processing-related corticotropin-releasing factor(CRF)receptor,glutamatergic NMDA receptor and GABA receptor subtype genes in the amygdala in chronic constrictive injury(CCI)of the sciatic nerve rats,so as to reveal its mechanism underlying pain relief.Methods Experiments were separately performed in 36 male Wistar rats which were randomized into normal control,CCI model and EA+CCI;normal control,CCI+negative affection(NA)model and CCI+NA+EA groups(n=6in each group).Neuropathic pain model was established by ligature of the left sciatic nerve,and NA model established by ligation of the left sciatic nerve and repeated skin stimulation(acupuncture needle pricking+direct current stimulation)of the paw-bottom,once daily for 3days.EA(2Hz/15 Hz,1mA)was applied to bilateral ST 36-GB 34 for 30min,once daily for 7days.Thermal pain threshold(paw withdrawal latency,PWL)of the bilateral paws was measured by using a Tail-Flick Unit 37360.Expression levels of CRF-1R,CRF-2R,NR 2A,NR 2B,GABAaR and GABAcR genes in the amygdala were determined using quantitative RT-PCR.Results In comparison with the normal control groups,PWL difference(PWLD)values of the bilateral paws of CCI model and CCI+NA model groups were significantly increased(P<0.05).In comparison with the model group,following 7days' EA stimulation,PWLD were considerably decreased(P<0.05),showing a pain relief.RT-PCR results indicated that compared to the normal control group,the expression levels of CRF-1R,CRF-2R,NR2 Aand NR 2Bgenes were apparently increased in the CCI model group(P<0.01,P<0.001),and those of CRF-1R,CRF-2R,NR 2A,NR 2B,GABAaR and GABAcR genes were remarkably down-regulated in the CCI+NA model group(P<0.05,P<0.01,P<0.001).After EA intervention for 7days,CRF-2R,NR 2Aand NR 2Bwere significantly down-regulated in the CCI+EA group,and CRF-1R,CRF-2R,NR 2B,GABAaR and GABAcR genes were obviously up-regulated in the CCI+NA+EA group(P<0.01,P<0.001).Conclusion Repeated EA stimulation of ST 36-GB 34 has a definite analgesic effect in neuropathic pain and negative affection rats,which may be respectively related to its effects in down-regulating expression of CRF-2R,NR 2Aand NR 2Bgenes,and up-regulating expression of CRF-1R,CRF-2R,NR 2B,GABAaR and GABAcR genes in the amygdala.