不同强度针刺对神经病理性镜像痛大鼠痛阈和脊髓背角磷酸化细胞外信号调节激酶表达的影响

目的:探讨不同强度针刺干预神经病理性镜像痛大鼠脊髓背角磷酸化细胞外信号调节激酶(p-ERK)表达的机制。方法:雄性SD大鼠随机分为空白对照组、模型组、弱刺激手针组、强刺激手针组,每组10只。模型组采用L 5脊神经结扎(SNL)法制备神经病理性镜像痛模型;弱刺激手针组于SNL术后3~11d隔日以细针(0.22mm×13mm)对双侧"环跳"穴进行针刺干预,幅度180°,频率60次/min,持续捻转2min后留针,15min时以相同强度再刺激1次,30min时出针;强刺激手针组以粗针(0.3mm×13mm)进行幅度360°、频率180次/min的针刺干预,其它操作与弱刺激手针组相同。于SNL前,SNL后3、7、12d时检测双侧后足机械痛阈。SNL后12d,各组随机取4只大鼠采用Western blot法检测双侧脊髓背角p-ERK的表达情况。结果:SNL后3、7、12d,与空白对照组比较,模型组同侧痛阈明显下降(P0.01);与模型组比较,7、12d时强刺激手针组同侧痛阈升高(P0.05,P0.01)。与空白对照组比较,SNL后7、12d时模型组对侧痛阈下降(P0.05);与模型组比较,SNL后7、12d时强刺激手针组对侧痛阈升高(P0.01)。模型组双侧脊髓背角p-ERK表达均高于空白对照组(P0.05),强刺激手针组双侧脊髓背角p-ERK表达均低于模型组(P0.05)。结论:强刺激手针缓解神经病理性镜像痛的机制可能与抑制双侧脊髓背角p-ERK的表达有关。

Effect of Mild and Strong Manual Acupuncture Stimulation of “Huantiao”(GB 30) on Mechanical Pain Thresholds and Extracellular Signal-regulated Kinase Protein Expression in Spinal Dorsal Horns in Rats with Neuropathic Mirror-image Pain

Objective To observe the effect of different intensities of manual acupuncture(MA)stimulation on mechanical pain thresholds(PTs)and the expression of phosphorylated extracellular signal-regulated kinases(p-ERK)in lumbar spinal dorsal horn regions in rats with neuropathic mirror-image pain,so as to explore its mechanisms underlying analgesia.MethodsForty male SD rats were equally and randomly divided into control,spinal nerve ligation(SNL)model,mild MA-stimulation,and strong MA-stimulation groups.Neuropathological pain model was established by ligature of the spinal nerve(L 5).Three days after the SNL,bilateral"Huantiao"(GB 30)were stimulated by rotating the thin(0.22mm×13mm)or thick(0.3mm×13mm)filiform needles at a frequencies of 60times/min or 180times/min and at an angle of 180°or 360°for 2min for rats in the mild and strong MA-stimulation groups,respectively,followed by remaining the needle in place for 30min.The mechanical PTs were measured before and after SNL.The expression of p-ERK protein in bilateral dorsal horn regions of the lumbar spinal cord(L 4-L 6)was detected by Western blot.Results In comparison with the control group,the mechanical PTs were significantly decreased beginning from the 3rd day on after SNL on the affected side and from the 7th day on after SNL on the healthy hindpaw(P<0.05),simultaneously,p-ERK protein expression levels of dorsal horn regions on both sides of the spinal cord were considerably up-regulated on the 12th day(P<0.05).Compared with the model group,the PTs of the affected hindpaw and the healthy hindpaw were significantly increased on the 7th and 12th day in the strong MA-stimulation group(P<0.05,P<0.01),whereas pERK expression levels in the bilateral spinal dorsal horn regions were obviously down-regulated in the strong MA-stimulation group(P<0.05).No significant differences were found between the model and mild MA-stimulation groups in the PTs of bilateral hindpaws and p-ERK expression levels of the bilateral spinal dorsal horn regions(P>0.05)except the PTs of the healthy hindpaw on 7th day(P<0.05).Conclusion Strong MA-stimulation can alleviate neuropathic mirror-image pain in SNL rats,which is closely related to its effect in down-regulating the expression of p-ERK in the bilateral spinal dorsal horn regions.