Pharmacological upregulation of GLT-1 alleviates the cognitive impairments in the animal model of temporal lobe epilepsy

PLoS One. 2021 Jan 28;16(1):e0246068. doi: 10.1371/journal.pone.0246068. eCollection 2021.

Abstract

It is known that hippocampal epileptogenesis is accompanied by hyperexcitability, glutamate-related neuronal dysfunctions and consequently cognitive deficits. However, the neuroprotective role of astrocytic glutamate uptake through the Glutamate Transporter-1 (GLT-1) remains to be unknown in these processes. Therefore, to assess the effect of glutamate uptake, pharmacological upregulation of GLT-1 using ceftriaxone administration (200 mg/kg/day, i.p, 5 days) was utilized in Li-PIL animal models of temporal lobe epilepsy (TLE). Glutamate concentration and glutamine synthetase activity were analyzed using biochemical assays. In addition, GLT-1 gene expression was assessed by RT-qPCR. Finally, cognitive function was studied using Morris water maze (MWM) test and novel object recognition task (NORT). Our results demonstrated that the acute phase of epileptogenesis (first 72 hours after Status Epilepticus) was accompanied by an increase in the hippocampal glutamate and downregulation of GLT-1 mRNA expression compared to controls. Ceftriaxone administration in epileptic animals led to a reduction of glutamate along with elevation of the level of glutamine synthetase activity and GLT-1 expression in the acute phase. In the chronic phase of epileptogenesis (4 weeks after Status Epilepticus), glutamate levels and GLT-1 expression were decreased compared to controls. Ceftriaxone treatment increased the levels of GLT-1 expression. Furthermore, impaired learning and memory ability in the chronic phase of epileptogenesis was rescued by Ceftriaxone administration. This study shows that astrocytic glutamate uptake can profoundly impact the processes of hippocampal epileptogenesis through the reduction of glutamate-induced excitotoxicity and consequently rescuing of cognitive deficits caused by epilepsy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Ceftriaxone / pharmacology
  • Ceftriaxone / therapeutic use
  • Cognitive Dysfunction / drug therapy*
  • Cognitive Dysfunction / metabolism
  • Disease Models, Animal
  • Epilepsy, Temporal Lobe / metabolism*
  • Excitatory Amino Acid Transporter 2 / metabolism*
  • Male
  • Maze Learning / drug effects
  • Neuroprotective Agents / pharmacology
  • Neuroprotective Agents / therapeutic use
  • Rats
  • Rats, Wistar
  • Recognition, Psychology / drug effects
  • Treatment Outcome
  • Up-Regulation / drug effects*

Substances

  • Excitatory Amino Acid Transporter 2
  • Neuroprotective Agents
  • Slc1a2 protein, rat
  • Ceftriaxone

Grants and funding

This study is supported by Ferdowsi University of Mashhad, Mashhad, Iran (grant No. 3/44083 confirmed on 17.03.1396 (22.05) to M.F.).