神经病理性疼痛大鼠脊髓背角Sirt1与miR-34b表达的变化

摘要

Objective To investigate the expression of Sirt1 and miR-34b in spinal cord of rats with neuropathic pain.Methods Fourteen male SD rats were randomly divided into sham operation group and sciatic nerve chronic constriction injury (CCI) group with 7 rats in each group.The mechanical withdrawal threshold (MWT) and thermal paw withdrawal threshold (TWL) of rats were determined at 1 d before and 7,14d after establishment of animal model.At d14 of CCI operation the animals were sacrificed and L4～5 segment of spinal cord was obtained,and the morphological changes of motor neurons in the dorsal horn of the spinal cord were observed with HE staining.Real-time PCR was used to detect the expression of Sirt1 and miR-34b in the dorsal horn of the spinal cord,and the protein expression of Sirt1,BDNF and CREB in rat spinal dorsal horn was determined by Western blot.Results The rat model of CCI were successfully established as tested by MWT and TWL.Histopathological observation showed that the number of spinal dorsal horn neurons was significantly decreased in CCI group after 7d and 14d (P＜0.05).Real-time PCR showed that Sirt1 expression was decreased and miR-34b expression was increased in CCI group compared with the control group (P＜0.05).Western blot showed that the expression of Sirt1 and CREB decreased,and the expression of pCREB and BDNF increased.Conclusion The expression changes of Sirt1 and miR-34b may be involved in the formation and maintenance of neuropathic pain induced by chronic constriction injury of sciatic nerve.%目的 研究Sirt1与miR-34b在神经病理性疼痛大鼠脊髓背角中表达变化的临床意义.方法 将14只雄性SD大鼠随机分为假手术组(Sham组)和坐骨神经慢性压迫性损伤组(CCI组),每组7只.于模型建立前1d及术后第7、14天,测定大鼠机械缩足反射阈值(MWT)和热缩足反射潜伏期(TWL).术后第14天取大鼠L4～５节段脊髓进行病理学检查,HE染色后观察脊髓背角运动神经元的数量变化.real-time PCR检测脊髓背角内Sirt1与miR-34b的表达,Western blot测定大鼠脊髓背角内Sirt1、脑源性神经营养因子(BDNF)和环磷腺苷效应元件结合蛋白(CREB)的表达.结果 经MWT和TWL验证,大鼠CCI神经病理性疼痛模型建立成功.HE染色显示,与Sham组比较,CCI组大鼠在手术后7、14d脊髓背角神经元数量显著减少(均P＜0.05).real-time PCR结果显示,与Sham组相比,CCI组Sirt1表达降低,miR-34b表达升高(均P＜0.05).Western blot显示Sirt1与CREB表达降低,pCREB与BDNF表达增加.结论 Sirt1与miR-34b的表达变化可能参与坐骨神经慢性压迫性损伤导致的神经病理性疼痛的形成和维持.