Experimental febrile seizures in young postnatal rats: Gender differences in long-lasting effect on the epileptic threshold and glial response.

ALICIA RAQUEL ROSSI; ALBERTO JAVIER RAMOS; FLORENCIA RODRIGUEZ; PAULA SARCHI

Mar del Plata

Congreso; Reunión Anual de Sciedades de Biociencia 2019; 2019

SAIC

Experimental febrile seizures in young postnatal rats:Gender differences in long-lasting effect on the epileptic threshold and glialresponse.Rossi, A; Rodríguez, F;Sarchi, P; Ramos, AJInstituto de BiologíaCelular y Neurociencia, Dr. E De Robertis. Facultad de Medicina. UBA  Febrile seizures occurs in 3?5% of childrenbetween 6 months and 5 years of age. Retrospective studies in adult epilepsypatients show an initial precipitating injury, usually febrile seizures, duringchildhood. Using an animal model of hyperthermic seizures (HS), we havepreviously shown that male HS-exposed animals exhibit a significativereduction in the convulsive threshold compared with controls and moderatereactive gliosis with an atypical astrocytes distribution in the pyriformcortex and other brain structures. Here we investigate consequences of early HSexposure in adolescent female rats compared to males. Rat pups (10-11 postnataldays old, PND) were placed in a glass chamber, and their core temperature wasraised by a regulated stream of moderately heated air (39-42°C). Bodytemperature was measure at baseline, seizure onset and every 2 min during theseizures. Hyperthermic temperatures (39.5?42.5 °C) were maintain for 30 min. The seizures onsetwas monitored behaviourally, and consisted of an acute sudden arrest ofhyperthermia-induced tonic freeze postures and occasional oral automatism(biting and chewing) and often body flexion. Rats were then placed on a coolsurface, monitored for 5 min before being returned to their mothers. AtPND37-39 rats were exposed to repeated pilocarpine subconvulsivedoses (10 mg/kg every thirty minutes). Another group of animals (PND35) wasdeeply anesthetized, fixed and brains processed forimmunohistochemistry. We observed that, contrary to the males, the females didnot develop SE after four repeated doses of pilocarpine and histologicalanalysis of their brains  exhibited lowerreactive gliosis compared to males. Our results suggest that HS exposure earlyin the postnatal brain development produce long-lasting effects in males, whichcould be related to their future susceptibility to develop epilepsy. Supported by grants: PICT 2015-1451; PICT 2017-2203;PIP CONICET, UBACYT