Caracterização do comportamento da pressão intracraniana pelos métodos de monitoramento minimamente invasivo e invasivo no modelo experimental de epilepsia da pilocarpina

Abstract

In this work, a new minimally invasive (ICPmi) and an invasive (ICPi) intracranial pressure (ICP) monitoring methods were used to evaluate intracranial pressure behavior in chronic epileptic rats, induced by the experimental model of pilocarpine. Using adult Wistar rats after three months from pilocarpine induced status epilepticus or control procedures, animals underwent a procedure for magnetic resonance imaging acquisition in order to verify volumetric changes in the hippocampal regions. Then, their ICPs were monitored simultaneously for 1 h using ICPmi and ICPi methods, followed by Neo-Timm histological processing of their brains after a week. Analyses consisted of spontaneous recurrent seizures (SRSs) frequency quantification for the pilocarpine group; and for both groups, volume determination of the hippocampal regions using MRI techniques, short-time Fourier transform for ICPi and spectral frequency determinations for ICPmi and ICPi, and mossy fiber sprouting presence verification. Spectral frequency analysis demonstrated a correspondence between ICPmi and ICPi in the frequency domain for both groups. For short-time Fourier transform analysis, oscillations along monitoring time in the ICP frequency were noticeable for the epileptic compared with the control animals. SRSs frequency quantification for the chronic epileptic animals showed an increasing number of seizures along experimental time. Tissue volume measurements for rostral, caudal and total hippocampus showed statistically significant reductions in the pilocarpine group compared to the control. All animals from the epileptic group presented mossy fiber sprouting in comparison with the control group. ICP characteristics of individuals with epilepsy are not elucidated in the literature, since there are few studies associating these two important neurological factors. This work is intended to provide a preliminary experimental approach to these topics of major public health importance.