title: Normobaric hyperoxia retards the evolution of ischemic brain tissue toward infarction in a rat model of transient focal cerebral ischemia.
abstract: OBJECTIVE
  Oxygen therapy has been long considered a logical therapy for ischemic stroke. Our previous studies showed that normobaric hyperoxia (normobaric hyperoxia (NBO), 95% O2 with 5% CO2) treatment during ischemia reduced ischemic neuronal death and cerebromicrovascular injury in animal stroke models. In this study, we studied the effects of NBO on the evolution of ischemic brain tissue to infarction in a rat model of transient focal cerebral ischemia.
  
  
  METHODS
  Male Sprague-Dawley rats were given NBO (95% O2) or normoxia (21% O2) during 90-min filament occlusion of the middle cerebral artery (MCAO), followed by 3 or 22.5 h of reperfusion. 2,3,5-triphenyltetrazolium chloride (TTC) staining was used to evaluate the longitudinal evolution of tissue infarction. Results： In normoxic rats, MCA-supplied cortical and striatal tissue was infarcted after 90-min MCAO with 22.5 h of reperfusion. NBO-treated rats showed a 61.4% reduction in infarct size and tissue infarction mainly occurred in the ischemic striatum. When infarction was assessed at an earlier time point, i.e. at 3 h of reperfusion, normoxic rats showed significantly smaller but mature infarction (no TTC staining, white color), with the infarction mainly occurring in the striatum. Unexpectedly, NBO-treated rats only showed immature lesion (partially stained by TTC, light white color) in the ischemic striatum, indicating that NBO treatment also retarded the process of neuronal death in the ischemic core. Of note, NBO-preserved striatal tissue underwent infarction after prolonged reperfusion. Conclusions： Our results demonstrate that NBO treatment given during cerebral ischemia retards the evolution of ischemic brain tissue toward infarction and NBO-preserved cortical tissue survives better than NBO-preserved striatal tissue during the phase of reperfusion.
authors.affiliation: a The Central Laboratory, Shenzhen 2nd People's Hospital , Shenzhen University 1st Affiliated Hospital , Shenzhen , China.|b Shenzhen Key Laboratory of Neurosurgery, Shenzhen 2nd People's Hospital , Shenzhen University 1st Affiliated Hospital , Shenzhen , China.|e Department of Anesthesiology, Shenzhen 2nd People's Hospital , Shenzhen University 1st Affiliated Hospital , Shenzhen , China.
authors.forename: Ji
authors.initials: J
authors.lastname: Xu
authors.affiliation: a The Central Laboratory, Shenzhen 2nd People's Hospital , Shenzhen University 1st Affiliated Hospital , Shenzhen , China.|b Shenzhen Key Laboratory of Neurosurgery, Shenzhen 2nd People's Hospital , Shenzhen University 1st Affiliated Hospital , Shenzhen , China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: a The Central Laboratory, Shenzhen 2nd People's Hospital , Shenzhen University 1st Affiliated Hospital , Shenzhen , China.|d Department of Neurology, Shenzhen 2nd People's Hospital , Shenzhen University 1st Affiliated Hospital , Shenzhen , China.
authors.forename: Zhouyuan
authors.initials: Z
authors.lastname: Liang
authors.affiliation: a The Central Laboratory, Shenzhen 2nd People's Hospital , Shenzhen University 1st Affiliated Hospital , Shenzhen , China.|b Shenzhen Key Laboratory of Neurosurgery, Shenzhen 2nd People's Hospital , Shenzhen University 1st Affiliated Hospital , Shenzhen , China.
authors.forename: Ting
authors.initials: T
authors.lastname: Wang
authors.affiliation: b Shenzhen Key Laboratory of Neurosurgery, Shenzhen 2nd People's Hospital , Shenzhen University 1st Affiliated Hospital , Shenzhen , China.|c Department of Neurosurgery, Shenzhen 2nd People's Hospital , Shenzhen University 1st Affiliated Hospital , Shenzhen , China.
authors.forename: Weiping
authors.initials: W
authors.lastname: Li
authors.affiliation: b Shenzhen Key Laboratory of Neurosurgery, Shenzhen 2nd People's Hospital , Shenzhen University 1st Affiliated Hospital , Shenzhen , China.|d Department of Neurology, Shenzhen 2nd People's Hospital , Shenzhen University 1st Affiliated Hospital , Shenzhen , China.
authors.forename: Lijie
authors.initials: L
authors.lastname: Ren
authors.affiliation: e Department of Anesthesiology, Shenzhen 2nd People's Hospital , Shenzhen University 1st Affiliated Hospital , Shenzhen , China.
authors.forename: Shaonong
authors.initials: S
authors.lastname: Huang
authors.affiliation: a The Central Laboratory, Shenzhen 2nd People's Hospital , Shenzhen University 1st Affiliated Hospital , Shenzhen , China.|b Shenzhen Key Laboratory of Neurosurgery, Shenzhen 2nd People's Hospital , Shenzhen University 1st Affiliated Hospital , Shenzhen , China.|c Department of Neurosurgery, Shenzhen 2nd People's Hospital , Shenzhen University 1st Affiliated Hospital , Shenzhen , China.
authors.forename: Wenlan
authors.initials: W
authors.lastname: Liu
mesh_terms: D000818:Animals; D020520:Brain Infarction / Q000209:etiology* / Q000517:prevention & control*; D004195:Disease Models, Animal; D006931:Hyperbaric Oxygenation / Q000379:methods*; D020244:Infarction, Middle Cerebral Artery / Q000150:complications* / Q000628:therapy; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D015424:Reperfusion; D013997:Time Factors
keywords: Neuroprotection; Oxygen; Stroke; infarction