title: Neuroprotection by hyperbaric oxygenation after experimental focal cerebral ischemia monitored by MRI.
abstract: BACKGROUND
  Hyperbaric oxygenation (HBO) after focal cerebral ischemia reduces infarct size and improves outcome when applied early after stroke. Here, we evaluated effects of HBO on permanent focal cerebral ischemia and applied magnetic resonance imaging (MRI) monitoring to study lesion evolution.
  
  
  METHODS
  Rats underwent permanent middle cerebral artery occlusion (MCAO). Two hours later, animals were treated with HBO (100% O(2)/2 atm; n=17) for 1 hour or treated with room air (n=17). Animals underwent serial MRI studies (DWI, PI, T2) beginning 90 minutes after MCAO. Neuroscore was assessed (5-point rating scale). Animals were euthanized and brains were 2,3,5-triphenyltetrazolium chloride (TTC)-stained for infarct volume calculation 120 hours after MCAO. Immunohistochemistry was performed with antibodies against c-FOS and 4-hydroxy-2-nonenal-modified proteins (HNE) to check for effects of oxidative stress caused by HBO treatment.
  
  
  RESULTS
  HBO reduced infarct volume by 38% (P<0.001). As shown by MRI, neuroprotection began 5 hours after ischemia and remained effective for 5 days. The relative regional cerebral blood flow was not different between groups at 3.5 and 5 hours after occlusion. There was less neurological deficit in HBO-treated animals compared with controls (P<0.05). Lipid peroxidation of cerebral vessels after HBO treatment as measured by HNE staining and pattern of c-FOS induction were not significantly different between groups at 3.5 and 8 hours after ischemia.
  
  
  CONCLUSIONS
  As monitored by MRI HBO treatment reversed ischemic lesion size between 3 and 5 hours after ischemia and achieved a long-lasting neuroprotective effect without significant oxidative damage.
authors.affiliation: Department of Neurology , University of Heidelberg, Germany.
authors.forename: Wolf-Ruediger
authors.initials: WR
authors.lastname: Schäbitz
authors.forename: Holger
authors.initials: H
authors.lastname: Schade
authors.forename: Sabine
authors.initials: S
authors.lastname: Heiland
authors.forename: Rainer
authors.initials: R
authors.lastname: Kollmar
authors.forename: Jürgen
authors.initials: J
authors.lastname: Bardutzky
authors.forename: Nils
authors.initials: N
authors.lastname: Henninger
authors.forename: Harald
authors.initials: H
authors.lastname: Müller
authors.forename: Ulrich
authors.initials: U
authors.lastname: Carl
authors.forename: Shinya
authors.initials: S
authors.lastname: Toyokuni
authors.forename: Clemens
authors.initials: C
authors.lastname: Sommer
authors.forename: Stefan
authors.initials: S
authors.lastname: Schwab
mesh_terms: D000818:Animals; D001273:Atmosphere Exposure Chambers; D002545:Brain Ischemia / Q000473:pathology / Q000517:prevention & control / Q000628:therapy*; D002540:Cerebral Cortex / Q000098:blood supply / Q000473:pathology; D002560:Cerebrovascular Circulation / Q000502:physiology; D004195:Disease Models, Animal; D005500:Follow-Up Studies; D006624:Hippocampus / Q000098:blood supply / Q000473:pathology; D006801:Humans; D006931:Hyperbaric Oxygenation / Q000379:methods*; D007150:Immunohistochemistry; D020244:Infarction, Middle Cerebral Artery / Q000473:pathology* / Q000517:prevention & control; D008279:Magnetic Resonance Imaging; D008297:Male; D018384:Oxidative Stress / Q000276:immunology / Q000502:physiology; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar