目的 探讨电针对神经病理性疼痛大鼠脊髓ERK1/2/P2X3信号通路的影响。方法 健康成年雄性SD大鼠50只，体重180~220 g，鞘内置管成功后随机分为五组（n=10）:假手术组（Sham组，分离坐骨神经不结扎）；手术组（CCI组，分离坐骨神经并用4-0丝线松结扎四道制备神经病理性疼痛模型）；穴位电针组（EA组，大鼠坐骨神经结扎后第4天开始电针患侧足三里-阳陵泉穴，连续6天，频率2Hz连续波，强度≤1.5mA，30min／次)；非穴位电针组（NA-EA组，电针患侧足三里外5mm和阳陵穴外5mm处非穴位点，余同EA组）；抑制剂组（U0126组，大鼠坐骨神经结扎后第4天开始鞘内给予U0126，5µg/次，每天2次，连续6天）。前4组各组坐骨神经结扎后d4开始鞘内给予5%二甲亚砜（dimethylsulfoxide, DMSO）溶剂对照，10µl/次，每天2次。术前一天（T0）和术后3,5,7,9天（T1~4）测定机械刺激缩足反应阈值（mechanical withdrawal threshold, MWT）和热刺激缩足反应潜伏期(thermal withdrawal latency, TWL)；于术后第10天处死大鼠，取右侧脊髓L4-6节段，Western-blot和反转录酶-聚合酶链锁反应(reverse transcription-polymerase chain reaction, RT-PCR)法分别检测P2X3受体蛋白和mRNA表达；Western-blot法测定细胞外信号调节激酶1/2（extracellular signal-regulated kinase1/2, ERK1/2）和磷酸化ERK1/2（p-ERK1/2）的表达。结果 与Sham组比较，其余各组大鼠MWT和TWL降低(P<0.05)，脊髓p-ERK1/2表达、P2X3受体蛋白和mRNA表达升高（P<0.05）；与CCI组比较，EA组及U0126组T2-4时MWT和TWL升高（P<0.05），P2X3蛋白和mRNA及p-ERK1/2表达降低（P<0.05），NA-EA组大鼠MWT和TWL变化及脊髓P2X3蛋白和mRNA及p-ERK1/2表达差异无统计学意义（P>0.05）。结论 电针足三里-阳陵泉穴可明显降低神经病理性疼痛大鼠脊髓背角P2X3受体表达，其机制可能与抑制ERK1/2信号通路有关。
Objective To investigate the effects of electroacupuncture(EA) on ERK1/2/P2X3 signal pathway in spinal cord of rats with neuropathic pain. Methods Fifty healthy male Sprague Dawley（SD） rats weighing 180~220 g，which showed no signs of never injury 2 days after inthethecal(i.t) catheterization with the tip of catheter reaching the lumbar region, were randomly divided into 5 groups(n=10 each): sham operation group(Sham group), CCI group, CCI+Aacupoint-EA(EA group), CCI+Nonacupoint-EA(NA-EA group), CCI+i.t U0126(U0126 group). CCI was induced by exposing the right sciatic nerve and placing 4 ligatures on the sciatic nerve at 1 mm intervals with 4-0 silk thread. In sham operation group the right sciatic nerve was exposed but not ligated. Electrical stimulation of Zusanli(ST36) and Yanglingquan(GB34) with 2 Hz continues frequency was performed once a day for 6 days(30 min/day) from 4th day after CCI. Nonacupoint was performed 5mm nearby the acupoint of ST36-GB34. The thermal withdrawal latency(TWL) was measured using hot plate test and mechanical withdrawal threshold(MWT) with von Frey filaments was measured for injured ipsilateral paw before and at days 3,5,7 and 9 after CCI operation(T0~4). The right lumbar segment (L4-6) of spinal cord was removed on the 10th day after induction of CCI for determination of the expression of P2X3 receptor, ERK1/2 and p-ERK1/2 in the spinal dorsal using western-blotting and P2X3 receptor mRNA expression by reverse transcription-polymerase chain reaction (RT-PCR). Results In comparison with sham group, MWT and TWL decreased significantly (P<0.05)and p-ERK expression and P2X3 receptor protein and mRNA levels were increased (P<0.05) after CCI in all other groups. Compared with CCI group, MWT and TWL increased at T2~4 and the protein and mRNA level of P2X3 and p-ERK expression decreased significantlyin EA and U0126 group(P<0.05)，but not changed significantly in NA-EA group(P>0.05). Conclusion EA alleviates neuropathic pain with acupoint specific, at least in part by suppressing P2X3 receptors in spinal cord, involving the signaling pathways of ERK1/2 partly.
Cited
)
