电针对神经病理性痛大鼠脊髓背角P2X4受体表达的影响

Effect of Electroacupuncture at Zusanli(ST36) and Yanglingquan(GB34) on Expression of P2X4 Receptor in Spinal Cord of CCI Rats

目的:通过观察电针干预慢性坐骨神经压迫性损伤(chronic constrictive injury,CCI)大鼠痛阈变化及脊髓背角P2X4受体的表达情况,探讨P2X4受体在电针镇痛效应中的作用。方法:18只SD大鼠随机分为3组:假模组(Sham Group)、模型对照组(CCI Group)和电针干预组(EA Group),CCI组及EA组结扎坐骨神经造成CCI疼痛模型,各组于术前(0 d)及术后20 d分别测量患侧足机械缩足反射阈值(MWT)和热缩足反射潜伏期(TWL),EA组于术后第5天电针"足三里"-"阳陵泉"连续14 d,1次/d。术后20 d取各组大鼠L4~6脊髓段用免疫荧光检测P2X4受体表达情况。结果:与术前比较,CCI大鼠痛阈明显降低,出现痛觉过敏(P<0.01),而电针干预后EA组较CCI模型组痛阈明显增加(P<0.05)但仍低于假模组。术后20 d EA组较CCI组脊髓背角中P2X4受体表达显著减少(P<0.05)。结论:脊髓背角P2X4受体参与了大鼠神经病理性疼痛的发生发展,电针可能通过抑制大鼠脊髓中P2X4受体的表达而产生镇痛作用。

Objective:To observe the underlying mechanisms of eletroacupuncture (EA)analgesic effect,we observed the effect of EA on the pain threshold change and the expression of P2X4 receptor in spinal cord of rats with neuropathic pain caused by chronic constriction injury(CCI).Methods:A total of 18SD rats were randomly divided into 3groups,including sham group,CCI group and EA group.The mechanical withdrawal threshold(MWT)and thethermal withdrawal latency(TWL)were measured before CCI operation and at day 14 after CCI operation.EA began at day 5 after CCI operation and then resumed once daily until the rats were killed at day 20 after the last EA treatment.EA was respectively applied to Zusanli(ST36)and Yanglingquan (GB34).At the day 20,the L4-6 spinal cord tissues were taken out for examing the expression of P2X4 receptor.Results :The values of MWT and TWL were decreased after CCI operation (P < 0.01),but EA could reverse this phenomenon (P <0.05).The expression of P2X4receptor in spinal cord was increased in the CCI group,but it could be inhibited significantly by EA treatment(P <0.01).Conclusion:These results suggested that P2X4receptor might be involved in the development of neuropathic pain.EA analgesia may be through decreasing the expression of P2X4receptor in the spinal cord of rats with CCI.