电针对神经病理性疼痛小鼠皮层miR-34a的影响

Involvement of miR-34a and p53 protein of cerebral cortex in electroacpuncture analgesia in mice with neuropathic pain

目的:观察电针对坐骨神经压迫性损伤(CCI)小鼠行为学及皮层miR-34a表达的影响,探讨miR-34a在电针镇痛效应中的作用。方法:将雄性C57BL/6小鼠随机分为假手术组、模型组、电针组,每组25只。结扎小鼠右侧坐骨神经制备神经病理性疼痛模型。电针组造模后当天及造模后第3、5、7天给予电针干预,每天1次,每次30 min,共干预4次。术后第3、5、7天检测各组小鼠左右后肢的机械缩足率和热刺激缩足潜伏期(PWL),实时荧光定量PCR法检测各组小鼠大脑皮层miR-34a的表达,Western blot法检测大脑皮层p53的表达。结果:与假手术组比较,模型组小鼠从造模后第3天开始右侧足底的机械缩足率明显上升、PWL明显降低(P<0. 05),造模后第3、5、7天小鼠左侧皮层miR-34a、p53的相对表达量明显升高(P<0. 05)。与模型组比较,电针组小鼠患侧机械缩足率降低、PWL升高(P<0. 05),左侧皮层miR-34a、p53的相对表达量明显降低(P<0. 05)。结论:电针干预可以改善神经病理性疼痛小鼠痛觉过敏,下调皮层miR-34a和p53的表达,提示miR-34a和p53可能参与电针抗神经病理性疼痛的效应。

ObjectiveTo explore the involvement of miR-34 a in cerebral cortex mediated anti-hyperalgesic effect of electroacupuncture(EA)in mice with neuropathic pain induced by chronic constriction injury(CCI)of sciatic nerve,so as to reveal its mechanisms underlying improvement of neuropathic pain.MethodsA total of 75 male C57 BL/6 mice were equally randomized into 3 groups:sham,CCI model and CCI+EA(n=25 in each group).Mice of the sham group received simple separation of the right sciatic nerve without ligation.The CCI model was established by liagation of the right sciatic nerve.EA(2 Hz/15 Hz,1 mA)was applied to bilateral'Zusanli'(ST36)and'Sanyinjiao'(SP9)for 30 min,once every other day.The mechanical and thermal pain threshold of the bilateral hind-paws was detected at the 3 rd,5 th and 7 thday after modeling,and the expression of miR-34 a of bilateral cerebral cortex tissues and that of p53 protein of the left cerebral cortex were determined by using quantitive real time PCR and Western blot,respectively.ResultsThe mechnical paw withdrawal frequency were significantly higher and the thermal paw withdrawal latencies(PWLs)were significantly shorter at the affected hind-limb(rather than at the healthy hind limb)on day 3,5 and 7 in the CCI model group than those in the sham group(P<0.05),and considerably reversed at the affected hind-limb(rather than at the healthy hind limb)in the EA group than in the CCI model group(P<0.05),suggesting an analgesic effect of EA intervention.After modeling,the expression levels of miR-34 a and p53 on day 3,5 and 7 were significantly up-regulated in the left cerebral cortex tissue(rather than in the right cerebral cortex)of the CCI model group in comparison with the sham group(P<0.05).After EA intervention,the up-regulated expression levels of miR-34 a and p53 in the left cerebral cortex tissue(rather than in the right cerebral cortex)were obviously suppressed in the EA group relevant to the CCI model group(P<0.05).ConclusionEA stimulation of ST36 and SP9 can down-regulate the expression of miR-34 a and p53 in the contra-lateral cerebral cortex tissue of the CCI mice,which may contribute to its anti-hyperalgesic effect.