Assessment of the progressive nature of cell damage in the pilocarpine model of epilepsy

Assessment of the progressive nature of cell damage in the pilocarpine model of epilepsy

Author Covolan, Luciene Autor UNIFESP Google Scholar
Mello, Luiz Eugenio Araujo de Moraes Autor UNIFESP Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Abstract Pilocarpine-induced (320 mg/kg, ip) status epilepticus (SE) in adult (2-3 months) male Wistar rats results in extensive neuronal damage in limbic structures. Here we investigated whether the induction of a second SE (N = 6) would generate damage and cell loss similar to that seen after a first SE (N = 9). Counts of silver-stained (indicative of cell damage) cells, using the Gallyas argyrophil III method, revealed a markedly lower neuronal injury in animals submitted to re-induction of SE compared to rats exposed to a single episode of pilocarpine-induced SE. This effect could be explained as follows: 1) the first SE removes the vulnerable cells, leaving behind resistant cells that are not affected by the second SE; 2) the first SE confers increased resistance to the remaining cells, analogous to the process of ischemic tolerance. Counting of Nissl-stained cells was performed to differentiate between these alternative mechanisms. Our data indicate that different neuronal populations react differently to SE induction. For some brain areas most, if not all, of the vulnerable cells are lost after an initial insult leaving only relatively resistant cells and little space for further damage or cell loss. For some other brain areas, in contrast, our data support the hypothesis that surviving cells might be modified by the initial insult which would confer a sort of excitotoxic tolerance. As a consequence of both mechanisms, subsequent insults after an initial insult result in very little damage regardless of their intensity.
Keywords Cell injury
Status epilepticus
Spontaneous seizures
Language English
Date 2006-07-01
Published in Brazilian Journal of Medical and Biological Research. Associação Brasileira de Divulgação Científica, v. 39, n. 7, p. 915-924, 2006.
ISSN 0100-879X (Sherpa/Romeo, impact factor)
Publisher Associação Brasileira de Divulgação Científica
Extent 915-924
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000239624200010
SciELO ID S0100-879X2006000700010 (statistics in SciELO)

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