Gabapentin administration reduces reactive gliosis and neurodegeneration after pilocarpine-induced status epilepticus

PLoS One. 2013 Nov 8;8(11):e78516. doi: 10.1371/journal.pone.0078516. eCollection 2013.

Abstract

The lithium-pilocarpine model of epilepsy reproduces in rodents several features of human temporal lobe epilepsy, by inducing an acute status epilepticus (SE) followed by a latency period. It has been proposed that the neuronal network reorganization that occurs during latency determines the subsequent appearance of spontaneous recurrent seizures. The aim of this study was to evaluate neuronal and glial responses during the latency period that follows SE. Given the potential role of astrocytes in the post-SE network reorganization, through the secretion of synaptogenic molecules such as thrombospondins, we also studied the effect of treatment with the α2δ1 thrombospondin receptor antagonist gabapentin. Adult male Wistar rats received 3 mEq/kg LiCl, and 20 h later 30 mg/kg pilocarpine. Once SE was achieved, seizures were stopped with 20 mg/kg diazepam. Animals then received 400 mg/kg/day gabapentin or saline for either 4 or 14 days. In vitro experiments were performed in dissociated mixed hippocampal cell culture exposed to glutamate, and subsequently treated with gabapentin or vehicle. During the latency period, the hippocampus and pyriform cortex of SE-animals presented a profuse reactive astrogliosis, with increased GFAP and nestin expression. Gliosis intensity was dependent on the Racine stage attained by the animals and peaked 15 days after SE. Microglia was also reactive after SE, and followed the same pattern. Neuronal degeneration was present in SE-animals, and also depended on the Racine stage and the SE duration. Polysialic-acid NCAM (PSA-NCAM) expression was increased in hippocampal CA-1 and dentate gyrus of SE-animals. Gabapentin treatment was able to reduce reactive gliosis, decrease neuronal loss and normalize PSA-NCAM staining in hippocampal CA-1. In vitro, gabapentin treatment partially prevented the dendritic loss and reactive gliosis caused by glutamate excitotoxicity. Our results show that gabapentin treatment during the latency period after SE protects neurons and normalizes PSA-NCAM probably by direct interaction with neurons and glia.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amines / administration & dosage*
  • Animals
  • Astrocytes / drug effects
  • Astrocytes / pathology
  • Cyclohexanecarboxylic Acids / administration & dosage*
  • Electroencephalography
  • Gabapentin
  • Gliosis / chemically induced
  • Gliosis / drug therapy*
  • Gliosis / physiopathology
  • Glutamic Acid / metabolism
  • Hippocampus / drug effects
  • Hippocampus / physiopathology
  • Humans
  • Male
  • Nestin / metabolism
  • Neuroglia / drug effects
  • Neuroglia / pathology
  • Neurons / drug effects
  • Neurons / pathology
  • Pilocarpine / toxicity
  • Rats
  • Seizures / chemically induced
  • Seizures / drug therapy*
  • Seizures / physiopathology
  • Status Epilepticus / chemically induced
  • Status Epilepticus / drug therapy*
  • Status Epilepticus / physiopathology
  • gamma-Aminobutyric Acid / administration & dosage*

Substances

  • Amines
  • Cyclohexanecarboxylic Acids
  • Nestin
  • Pilocarpine
  • Glutamic Acid
  • gamma-Aminobutyric Acid
  • Gabapentin

Grants and funding

The work has been founded by ANPCYT-FONCYT grant Nr. PICT 2008-1590 (http://www.agencia.mincyt.gob.ar/frontend/agencia/fondo/foncyt) CONICET grant PIP 1728/2009 (www.conicet.gov.ar) and University of Buenos Aires grant Nr. 20020110100141. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.