Co-administration of subtherapeutic diazepam enhances neuroprotective effect of COX-2 inhibitor, NS-398, after lithium pilocarpine-induced status epilepticus

Neuroscience. 2015 Jan 22:284:601-610. doi: 10.1016/j.neuroscience.2014.10.021. Epub 2014 Oct 18.

Abstract

Rationale: Seizures during status epilepticus (SE) cause neuronal death and induce cyclooxygenase-2 (COX-2). Pilocarpine-induced SE was used to determine if COX-2 inhibition with NS-398, when administered alone or with diazepam, decreases the duration and/or intensity of SE and/or reduces neuronal injury in the rat hippocampus.

Methods: Electroencephalogram (EEG) electrodes were implanted in male Sprague-Dawley rats. SE was induced with lithium-pilocarpine, and continuous EEG and video monitoring were performed for 24 h. Rats were divided into four groups (n=8-14 rats/group) and received NS-398, diazepam, NS-398 and diazepam, or vehicle 30 min after the first motor seizure. Six hours later, NS-398 injection was repeated in the NS-398 and in the NS-398+diazepam groups. The duration of SE (continuous spiking) and the EEG power in the γ-band were analyzed. FluoroJade B staining in the dorsal hippocampus at 24h after SE was analyzed semi-quantitatively in the CA1, CA3 and hilus.

Results: The duration and intensity of electrographic SE was not significantly different across the four groups. In rats treated with NS-398 alone, compared to vehicle-treated rats, neuronal damage was significantly lower compared to vehicle-treated rats in the CA3 (27%) and hilus (27%), but neuroprotection was not detected in the CA1. When NS-398 was administered with diazepam, decreased neuronal damage was further obtained in all areas investigated (CA1: 61%, CA3: 63%, hilus: 60%).

Conclusions: NS-398, when administered 30 min after the onset of SE with a repeat dose at 6h, decreased neuronal damage in the hippocampus. Administration of diazepam with NS-398 potentiates the neuroprotective effect of the COX-2 inhibitor. These neuroprotective effects occurred with no detectable effect on electrographic SE.

Keywords: cyclooxygenase-2 (COX-2); inflammation; neuroprotection.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Anticonvulsants / administration & dosage*
  • Cyclooxygenase 2 / metabolism
  • Cyclooxygenase 2 Inhibitors / administration & dosage
  • Diazepam / administration & dosage*
  • Disease Models, Animal
  • Drug Therapy, Combination / methods
  • Electrodes, Implanted
  • Electroencephalography
  • Hippocampus / drug effects*
  • Hippocampus / pathology
  • Hippocampus / physiopathology
  • Lithium Compounds
  • Male
  • Neurons / drug effects
  • Neurons / pathology
  • Neurons / physiology
  • Neuroprotective Agents / administration & dosage*
  • Nitrobenzenes / administration & dosage*
  • Pilocarpine
  • Rats, Sprague-Dawley
  • Status Epilepticus / drug therapy*
  • Status Epilepticus / pathology
  • Status Epilepticus / physiopathology
  • Sulfonamides / administration & dosage*
  • Video Recording

Substances

  • Anticonvulsants
  • Cyclooxygenase 2 Inhibitors
  • Lithium Compounds
  • Neuroprotective Agents
  • Nitrobenzenes
  • Sulfonamides
  • Pilocarpine
  • N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide
  • Cyclooxygenase 2
  • Ptgs2 protein, rat
  • Diazepam