Objective 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.