title: Extended normobaric hyperoxia therapy yields greater neuroprotection for focal transient ischemia-reperfusion in rats.
abstract: BACKGROUND
  Normobaric hyperoxia (NBO) therapy is neuroprotective in acute ischemic stroke. However, how long the NBO should last to obtain optimal outcome is still unclear. Reports show that ischemic penumbra blood supply may remain compromised for a long period after ischemia-reperfusion, which would impair tissue oxygenation in ischemic penumbra. Therefore, we hypothesized that longer-lasting NBO may yield greater neuroprotection.
  
  
  METHODS
  The relationship between treatment outcome and NBO duration was examined in this study. Rats were subjected to 90 min middle cerebral artery occlusion followed by reperfusion for 22.5 hours. NBO started at 30 min post ischemia and lasted for 2, 4 or 8 h. Treatment efficacy was evaluated by measuring infarction volume, oxidative stress and apoptosis.
  
  
  RESULTS
  Among 2 h, 4 h and 8 h NBO, 8 h NBO offered the greatest efficacy in reducing 24-hour infarction volume, attenuating oxidative stress that was indicated by decreased production of 8-hydroxydeoxyguanosine and NADPH oxidase catalytic subunit gp91(phox), and alleviating apoptosis that was associated with reduced production of DNA fragment and caspase-3 activity in cortex penumbra.
  
  
  CONCLUSIONS
  Under our experimental conditions, longer duration of NBO treatment produced greater benefits in focal transient cerebral ischemia-reperfusion rats.
authors.affiliation: College of Pharmacy, University of New Mexico Health Sciences Center, MSC09 5360, Albuquerque, NM 87131-0001, USA ; College of Medicine, Shandong University, Jinan 250012, China.
authors.forename: Zhongrui
authors.initials: Z
authors.lastname: Yuan
authors.affiliation: College of Pharmacy, University of New Mexico Health Sciences Center, MSC09 5360, Albuquerque, NM 87131-0001, USA.
authors.forename: Rong
authors.initials: R
authors.lastname: Pan
authors.affiliation: College of Pharmacy, University of New Mexico Health Sciences Center, MSC09 5360, Albuquerque, NM 87131-0001, USA.
authors.forename: Wenlan
authors.initials: W
authors.lastname: Liu
authors.affiliation: College of Pharmacy, University of New Mexico Health Sciences Center, MSC09 5360, Albuquerque, NM 87131-0001, USA.
authors.forename: Ke Jian
authors.initials: KJ
authors.lastname: Liu
keywords: Apoptosis; Ischemic stroke; Normobaric hyperoxia; Oxidative stress; Tissue oxygenation