电针对大鼠神经病理性疼痛及背根神经节中p38 MAPK蛋白表达的影响

摘要

目的:观察电针刺激“足三里”穴位对大鼠神经病理性疼痛的影响,及电针治疗对大鼠背根神经节中p38丝裂原活化蛋白激酶(p38 mitogen-activated protein kinase,p38 MAPK)信号转导途径的影响.方法:40只雄性Wistar大鼠随机均分为4组(n=10):空白对照组(Con组)；坐骨神经结扎组(CCI组)；假电针治疗组(CCI+A组);电针治疗组(CCI+EA组).分别于实验前及坐骨神经结扎后第7、14、21 d,观察并记录大鼠的热缩足反射潜伏期(paw withdrawal latency,PWL)和机械缩足反应阈值(paw withdrawal threshold,PWT)变化和大鼠受累后肢的运动功能评分.在实验结束(即第21 d)时,处死大鼠,取出右侧L4～6节段的背根神经节,之后采用免疫组化的方法检测大鼠背根神经节中p38MAPK蛋白的表达.结果:PWT和PWL在Con组中没有变化,而在CCI组和CCI+A组中显著降低,并持续至实验结束.CCI+EA组在电针治疗后PWT和PWL与CCI组和CCI+A组相比显著升高(P＜0.05).电针治疗后,CCI+EA组大鼠受累后肢的运动评分显著低于CCI+A组和CCI组(P＜0.05).免疫组化结果显示:CCI+EA组大鼠背根神经节中的磷酸化p38MAPK (phosphor-p38 MAPK,p-p38 MAPK)阳性细胞表达均显著低于CCI组和CCI+A组(P＜0.05).结论:电针刺激“足三里”穴位能够减轻神经病理性疼痛大鼠的热痛和机械痛,改善大鼠受累后肢的运动功能评分；电针抑制CCI大鼠背根神经节中p38MAPK的表达.%Objective:To observe the analgesic effect of electroacupuncture (EA) on "Zusanli" acupoint (ST36) in neuropathic pain and the effect of EA on the expression of p38 mitogen-activated protein kinase (p38 MAPK) in rats.Methods:Forty male Wistar rats were equally and randomly divided into four groups (n =10):The control group,the CCI group,the CCI+A group,and the EA group.The paw withdrawal latency (PWL) and paw withdrawal threshold (PWT) were measured before the experiment and at the 7th,14th,and the 21st day after the CCI surgery,and the motor function of the right hind limb was evaluated at the same time.At the end of the experiment (the 21st day),the rats were executed and then the dorsal root ganglia of the L4～6 in the right side were dissected.After that the expression of p38 MAPK protein in the dorsal root ganglia was detected by immunohistochemistry analyses.Results:The PWT and PWL was stable in the control group,and was decreased significantly in the CCI group and the CCI+A group,which lasted to the end of the experiment.After the EA treatment,The PWT and PWL in the CCI+EA group were significantly higher than the CCI group and CCI+A group (P ＜ 0.05).After the EA treatment,the motor function of the affected hind limb in the CCI+EA group was improved significantly compared with the CCI group and CCI+A group (P ＜ 0.05).The immunohistochemisty results showed that the phosphor-p38MAPK (p-p38 MAPK) expression in the dorsal root ganglia was significantly decreased compared with the CCI group and CCI+A group (P ＜ 0.05).Conclusions:Electroacupuncture on "Zusanli" acupoint decreased the thermal pain and mechanical pain,and improved the motor function of the lesions limb in neuropathic pain rats.The electroacupuncture inhibited the phosphor-p38 MAPK protein expression in the dorsal root ganglia of CCI rats.