The role of trace elements in the pathogenesis and progress of pilocarpine-induced epileptic seizures

Abstract

Epilepsy, the third most common neurological disorder, is characterized by recurrent unprovoked seizures. Although the mechanisms of epileptic convulsions have been a subject of intensive investigations for many years in most cases the etiology of the disease is not known [1].Metallic elements participating in the processes like: oxidative stress, excitotoxicity, mitochondrial dysfunction or protein aggregation may lead to the atrophy and death of neurons in case of some neurodegenerative disorders [2][3][4]. Because epileptic seizures induce neurodegeneration in selected areas of brain it is suspected that metals may be involved in the pathogenesis and progress of epilepsy as well [5].Existing evidence suggests that epileptic seizures significantly change metabolism and distribution of trace elements in the nervous tissue [6][7][8]. From the other hand, content of metals determinates susceptibility to convulsions [9].In our experiment we used pilocarpine in order to induce epilepsy in rats. In order to find what elements are involved in the pathogenesis and progress of epileptic convulsions the comparison between pilocarpine treated and control rats was done. The samples of rat brain were cut using a cryomicrotome into 15 µm thick slices. Thin tissue sections were mounted on Ultralene foil and freeze-dried.X-ray fluorescence microscopy was employed for topographic and quantitative analysis of selected metals in the areas of brain tissue involved in epilepsy. The measurements were done on the bending magnet beamline L at HASYLAB. The multilayer monochromator was applied and the primary photon energy was set to 17 keV. The beam was focused with polycapillary optics for a final beam spot dimension of 15 µm x 15 µm. The characteristic X-ray lines were measured using the Vortex SDD detector from SII Nano Technology USA inc. and the time of spectra acquisition was equal to 6 s per pixel. Measurements of NIST standard reference materials (SRM 1833 and SRM 1832) were performed for spectrometer calibration.The elements such us P, S, Cl, K, Ca, Fe, Cu, Zn, Br, Rb and Sr were detected in rat brain sections. For each sample two-dimensional analysis of elemental distribution was performed for the area of hippocampus and brain cortex. The results of such analysis for selected control and epileptic sample were shown in Figures 1 and 2 respectively.For four regions of hippacampus formation (CA1 -Cornu Ammonis, CA3, DG -Dentate Gyrus and H -Hilus) and motor cortex the mean masses per unit area were evaluated. The areas taken into account in calculations were equal to 300 µm per 300 µm. The preliminary results showed that the level of Ca tends to be higher for CA1 region of hippocampus and cortex in case of animals with pilocarpine induced epilepsy. The opposite relation was observed for Zn level in the area of DG.1551

Synchrotron FTIR micro-spectroscopy study of the rat hippocampal formation after pilocarpine-evoked seizures

“…In this work 10-mm IR beam was used to analyze biochemical composition of DG and CA3 hippocampal areas. The mentioned sectors of the hippocampal formation were chosen based on our previous studies concerning the elemental abnormalities occurring in the brain tissue as a consequence of pilocarpine-induced seizures (Chwiej et al, 2008).…”

Variations in elemental compositions of rat hippocampal formation between acute and latent phases of pilocarpine-induced epilepsy: an X-ray fluorescence microscopy study

“…This article is a continuation of our previous studies which analyzed changes in the accumulation of metals resulting from seizures, mechanical brain injury, and the use of the neuroprotective agent FK-506 [5][6][7]. We try to verify whether the compositional changes of Ca, Cu, and Zn [5], observed before for the acute period of pilocarpineinduced status epilepticus, were temporary or permanent irreversible effects.…”

“…We try to verify whether the compositional changes of Ca, Cu, and Zn [5], observed before for the acute period of pilocarpineinduced status epilepticus, were temporary or permanent irreversible effects. To achieve this, rats classified in the second period of the pilocarpine model of epilepsy are examined.…”

Various ketogenic diets can differently support brain resistance against experimentally evoked seizures and seizure-induced elemental anomalies of hippocampal formation

“…The net peak areas of K-α lines of the analyzed elements obtained from PyMCA together with elemental sensitivities calculated based on measurements of calibration standards were used to calculate elemental areal densities for the examined tissue points. The steps of calculation were presented in details elsewhere [26].…”