Background and aims This study investigated the dynamic expression pattern of interleukin-1β and tumour necrosis factor alpha (TNF-α) as a proinflammatory cytokines and microRNA (miR)-146a and miR-155 as a posttranscriptional inflammation- related miRs in the hippocampi of an immature rat model andchildren with MTLE.

Methods To study the expression of IL-1β, TNF-α, miR-146a and miR-155, we performed a reverse transcription polymerase chain reaction, Western blot, andreal-time quantitative PCR on the hippocampi of immature rats. Expressions were monitored in the acute, latent, and chronic stages of disease (2 h and 3 and 8 weeks after induction of lithium-pilocarpine status epilepticus, respectively), and in control hippocampal tissues corresponding to the same timeframes. Similar expression methods were applied to hippocampi obtained from children with MTLE and normal controls.

Results The expression of IL-1β, TNF-α, miR-146a and miR-155 were up-regulated in children with MTLE. In the immature rat model, IL-1β and miR-146a are significantly up-regulated, but in opposite ways: in the acute stage IL-1β expression is highest, when miR-146a expression is at its lowest level; thereverse of this expression occurs in the latent stage, while both are up-regulated in the chronic stage. TNF-α and miR-155 dynamic expressions showed the same fluctuating upregulation in the three stages of the MTLE development.

Conclusion The dynamic expressions of (IL-1β and miR-146a) and (TNF-α and miR-155) in the different stages of MTLE suggesting an interactive relationship. Therefore, modulation of IL-1β–miR-146a and TNF-α–miR-155 axesmay be novel therapeutic targets in the treatment of MTLE.