title: Cerebral edema induced in mice by a convulsive dose of soman. Evaluation through diffusion-weighted magnetic resonance imaging and histology.
abstract: OBJECTIVE
  In the present study, diffusion-weighted magnetic resonance imaging (DW-MRI) and histology were used to assess cerebral edema and lesions in mice intoxicated by a convulsive dose of soman, an organophosphate compound acting as an irreversible cholinesterase inhibitor.
  
  
  METHODS
  Three hours and 24 h after the intoxication with soman (172 microg/kg), the mice were anesthetized with an isoflurane/N(2)O mixture and their brain examined with DW-MRI. After the imaging sessions, the mice were sacrificed for histological analysis of their brain.
  
  
  RESULTS
  A decrease in the apparent diffusion coefficient (ADC) was detected as soon as 3 h after the intoxication and was found strongly enhanced at 24 h. A correlation was obtained between the ADC change and the severity of the overall brain damage (edema and cellular degeneration): the more severe the damage, the stronger the ADC drop. Anesthesia was shown to interrupt soman-induced seizures and to attenuate edema and cell change in certain sensitive brain areas. Finally, brain water content was assessed using the traditional dry/wet weight method. A significant increase of brain water was observed following the intoxication.
  
  
  CONCLUSIONS
  The ADC decrease observed in the present study suggests that brain edema in soman poisoning is mainly intracellular and cytotoxic. Since entry of water into the brain was also evidenced, this type of edema is certainly mixed with others (vasogenic, hydrostatic, osmotic). The present study confirms the potential of DW-MRI as a non-invasive tool for monitoring the acute neuropathological consequences (edema and neurodegeneration) of soman-induced seizures.
authors.affiliation: Centre de Recherches du Service Santé des Armées, Département de Toxicologie, BP87, F-38702 La Tronche cedex, France. guytestylier@crssa.net
authors.forename: Guy
authors.initials: G
authors.lastname: Testylier
authors.forename: Hana
authors.initials: H
authors.lastname: Lahrech
authors.forename: Olivier
authors.initials: O
authors.lastname: Montigon
authors.forename: Annie
authors.initials: A
authors.lastname: Foquin
authors.forename: Claire
authors.initials: C
authors.lastname: Delacour
authors.forename: Denis
authors.initials: D
authors.lastname: Bernabé
authors.forename: Christoph
authors.initials: C
authors.lastname: Segebarth
authors.forename: Frédéric
authors.initials: F
authors.lastname: Dorandeu
authors.forename: Pierre
authors.initials: P
authors.lastname: Carpentier
mesh_terms: D000758:Anesthesia; D018685:Anesthetics, Inhalation; D000818:Animals; D001834:Body Water / Q000378:metabolism; D001921:Brain / Q000473:pathology; D001929:Brain Edema / Q000139:chemically induced* / Q000473:pathology*; D003292:Convulsants / Q000506:poisoning*; D038524:Diffusion Magnetic Resonance Imaging; D004569:Electroencephalography / Q000187:drug effects; D007090:Image Interpretation, Computer-Assisted; D007530:Isoflurane; D008297:Male; D051379:Mice; D009609:Nitrous Oxide; D012999:Soman / Q000506:poisoning*
chemical_list: D018685:Anesthetics, Inhalation; D003292:Convulsants; D012999:Soman; D007530:Isoflurane; D009609:Nitrous Oxide