摘要目的 探讨microRNA(miR)-34a和Notch1信号通路在颞叶癫痫模型大鼠海马中的表达及作用机制.方法 将大鼠根据随机数字表法分为模型组(40只)和对照组(40只),模型组采用腹腔注射氯化锂-匹罗卡品建立颞叶癫痫模型;对照组注射等量9 g/L盐水.在建模后24 h、3 d、7 d、15 d、1 个月采用Racine分级法评估大鼠行为学改变;实时荧光定量聚合酶链式反应检测海马中miR-34a及Notch1 mRNA 的表达水平;Western blot检测Notch1蛋白的表达水平.结果 模型组miR-34a 24 h、3 d、7 d、15 d时表达水平分别为2.55±0.29、2.11±0.17、1.68±0.49、1.84±0.42,与对照组(1.00±0.00)比较差异均有统计学意义(t=-1.55、-1.11、-0.68、-0.84,均P<0.05).模型组Notch1 mRNA 24 h、3 d、7 d、15 d、1个月时表达水平分别为1.44±0.31、1.27±0.13、1.52±0.28、0.91±0.33、0.80±0.09,24 h和7 d表达水平与对照组(1.00±0.00)比较差异均有统计学意义(t=-0.44、-0.52,均 P<0.05).模型组15 d时Notch1 mRNA表达水平较24 h和 7 d 降低(t=-0.54、-0.62);1 个月时表达水平较24 h、3 d、7 d 降低(t=-0.64、-0.46、-0.72),差异均有统计学意义(均P<0.05).模型组Notch1蛋白24 h、3 d、7 d、15 d、1个月时表达水平分别为0.78±0.09、0.57±0.13、0.55±0.16、0.42±0.13、0.33±0.09,24 h时表达水平与对照组(0.51±0.15)比较差异有统计学意义(t=-0.20,P<0.05).模型组Notch1蛋白15 d时表达水平较24 h降低(t=-0.26,P<0.05);1 个月时表达水平较24 h、3 d降低(t=-0.36、-0.24),差异均有统计学意义(均P<0.05).结论 颞叶癫痫大鼠模型海马中miR-34a表达水平上调,可能通过激活Notch1信号通路参与癫痫的发生与发展.

abstractsObjective To explore the expression levels of microRNA(miR)-34a in hippocampus of temporal lobe epilepsy rats and the effect of miR-34a on its target signaling pathway Notch1.Methods Rats were divided randomly into experiment group (n=40) and control group (n=40) by adopting random number table method.The status epilepticus model and the temporal lobe epilepsy model were induced by using lithium-pilocarpine for experiment group.The control group rats received an injection of an equal amount of 9 g/L saline as instead of pilocarpine.Racine grading was performed at 24 hours,day 3,day 7,day 15,and 1 month after modeling to evaluate the behavior.Real-time fluorescent quantitative polymerase chain reaction was used to test the mRNA expressions of miR-34a and Notch1.Western blot was performed to explore the protein expression of Notch1.Results The expression levels of miR-34a at post-status epilepticus in 24 hours,day 3,day 7,day 15 were 2.55±0.29,2.11±0.17,1.68±0.49 and 1.84±0.42,respectively,which showed statistically significant difference compared with the control group (1.00±0.00) (t=-1.55,-1.11,-0.68,-0.84,all P<0.05).The expression levels of Notch1 mRNA at post-status epilepticus in 24 hours,day 3,day 7,day 15,1 month were 1.44±0.31,1.27±0.13,1.52±0.28,0.91±0.33,and 0.80±0.09 respectively.There were significant differences at 24 hours,day 7 in Notch1 mRNA expression (t=-0.44,-0.52,all P<0.05) compared with the control group(1.00±0.00).The expression level of Notch1 mRNA on day 15 was significantly lower than 24 hours and day 7 (t=-0.54,-0.62,all P<0.05),and the expression in 1 month was significantly lower than in 24 hours,or day 3 and day 7 (t=-0.64,-0.46,-0.72,all P<0.05).The expression levels of Notch1 protein at post-status epilepticus 24 hours,day 3,day 7,day 15,1 month were 0.78±0.09,0.57±0.13,0.55±0.16,0.42±0.13,and 0.33±0.09,respectively.There was significantly up-regulated at 24 hours of Notch1 protein expression compared with control group (0.51±0.15)(t=-0.20,P<0.05);and the expression level at day 15 were significantly lower than 24 hours (t=-0.26,P<0.05),while the expression in 1 month was significantly lower than in 24 hours and on day 3 (t=-0.36,-0.24,all P<0.05).Conclusion miR-34a is significantly up-regulated in the post-status epilepticus rat hippocampus,and it may contribute to temporal lobe epilepsy by activating Notch1 signaling pathway.