Extended normobaric hyperoxia therapy yields greater neuroprotection for focal transient ischemia-reperfusion in ratsReport as inadecuate




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Medical Gas Research

, 4:14

Oxygen and diving medicine

Abstract

BackgroundNormobaric 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.

MethodsThe 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.

ResultsAmong 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, and alleviating apoptosis that was associated with reduced production of DNA fragment and caspase-3 activity in cortex penumbra.

ConclusionsUnder our experimental conditions, longer duration of NBO treatment produced greater benefits in focal transient cerebral ischemia-reperfusion rats.

KeywordsApoptosis Ischemic stroke Normobaric hyperoxia Oxidative stress Tissue oxygenation AbbreviationsNBONormobaric hyperoxia therapy

MCAOMiddle cerebral artery occlusion

ECAExternal carotid artery

LDFLasr Doppler flowmetry

TTC2,3,5-triphenyltetrazolium chloride

TUNELTerminal deoxynucleotidyl transferase-mediated uridine 5’-triphosphate-biotin nick end labeling

8-OHdG8-hydroxy-deoxyguanosine

TdTTerminal deoxynucleotidyl transferase.

Electronic supplementary materialThe online version of this article doi:10.1186-2045-9912-4-14 contains supplementary material, which is available to authorized users.

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Author: Zhongrui Yuan - Rong Pan - Wenlan Liu - Ke Jian Liu

Source: https://link.springer.com/







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