Authors :
Presenting Author: Joonwon Kang, MD, PhD – Chungnam National University School of Medicine
Qiaoling liu, BS – Research Assistant, Pediatrics, University of Nebraska; Sookyong Koh, MD PhD – Professor, Pediatrics, University of Nebraska
Rationale:
The NLRP3 Inflammasome has been implicated in the pathogenesis of febrile-infection related epilepsy syndrome (FIRES). A functional deficiency in endogenous IL-1 receptor antagonist (IL-1Ra) activity found in patients in FIRES may lead to an unopposed pathological inflammatory state driven by over-active IL-1β, a master cytokine of innate immunity and local and systemic inflammation. Given the compromised IL-1Ra function in FIRES patients, we chose to utilize IL-1Ra deficient mice to model FIRES. We exposed IL-1Ra deficient mice to experimentally induced fever at postnatal day (P) 25, followed by intrahippocampal kainic acid (IHKA)-injection at P30 or P40 to induce status epilepticus (SE) and monitored them for spontaneous recurrent seizures over 3 weeks.
Methods:
Breeding pairs of IL-1Ra (+/-) mice were purchased from Jackson Laboratory. To mimic febrile illness history of FIRES patients, we exposed three groups of P25 mice, wild type (WT n=16), heterozygous (HET n=15), and knock-out (KO n=16), to experimental fever (lipopolysaccharide (LPS) + hyperthermia). Mice were injected with LPS (100 ug/kg i.p.) 2 h before exposure to a heat lamp to raise the core temperature to 41°C for 30 minutes. Mice were injected with IHKA (150 nl x 1 mg/ml) stereotactically either at P30 (P25-P30 group; WT 7, HET 6, KO 8) or at P40 (P25-P40 group; WT 9, HET 9, KO 8). Electroencephalographic (EEG) (Pinnacle) was implanted at P40 and 48-h EEG was obtained at two and three weeks post-IHKA-SE. Electrographic seizures were defined as rhythmic EEG activity lasting 10 s or longer that exceeds the baseline amplitude by at least threefold. Kruskal-Wallis and Mann-Whitney tests (Prism v. 5.0, GraphPad) were used for statistical analysis, and significance was defined as p< 0.05.