Expression profile of microRNAs in rat hippocampus following lithium–pilocarpine-induced status epilepticus

Although microRNAs are expressed extensively in the central nervous system in physiological and pathological conditions, their expression in neurological disorder of epilepsy has not been well characterized. Here we investigated microRNA expression pattern in post status epilepticus rats (24 h after status). Rat MicroRNA array and differential analysis had detected 19 up-regulated microRNAs and 7 down-regulated microRNAs in rat hippocampus, and four randomly selected deregulated microRNAs (microRNA-34a, microRNA-22, microRNA-125a, microRNA-21) were confirmed by qRT-PCR, then their expression alterations in rat peripheral blood were analyzed. We found that these four deregulated microRNAs were also differentially expressed in rat peripheral blood, and trends for their blood expression alterations were just the same as their counterparts in rat hippocampus. Thus, our results have not only characterized the microRNA expression profile in post status epilepticus rat hippocampus but also demonstrated that some rat hippocampal microRNAs were probably associated with rat peripheral blood microRNAs. Moreover, targets of these deregulated microRNAs were analyzed using bioinformatics and the identified enriched MAPK pathway and long-term potentiation pathway might have been involved in molecular mechanisms concerning neuronal death, inflammation and epileptogenesis.

Research highlights▶ Status epilepticus leads to an aberrant miRNA expression pattern in rat hippocampus. ▶ There are 26 deregulated miRNAs in post status epilepticus rat hippocampus. ▶ Peripheral blood and hippocampal miRNAs are probably correlated in epilepsy rats. ▶ The MAPK pathway might be involved in neuronal death and inflammatory process. ▶ The long-term potentiation pathway might be involved in epileptogenesis.