Nox2 knockout delays infarct progression and increases vascular recovery through angiogenesis in mice following ischaemic stroke with reperfusion

PLoS One. 2014 Nov 6;9(11):e110602. doi: 10.1371/journal.pone.0110602. eCollection 2014.

Abstract

Evidence suggests the NADPH oxidases contribute to ischaemic stroke injury and Nox2 is the most widely studied subtype in the context of stroke. There is still conjecture however regarding the benefits of inhibiting Nox2 to improve stroke outcome. The current study aimed to examine the temporal effects of genetic Nox2 deletion on neuronal loss after ischaemic stroke using knockout (KO) mice with 6, 24 and 72 hour recovery. Transient cerebral ischaemia was induced via intraluminal filament occlusion and resulted in reduced infarct volumes in Nox2 KO mice at 24 h post-stroke compared to wild-type controls. No protection was evident at either 6 h or 72 h post-stroke, with both genotypes exhibiting similar volumes of damage. Reactive oxygen species were detected using dihydroethidium and were co-localised with neurons and microglia in both genotypes using immunofluorescent double-labelling. The effect of Nox2 deletion on vascular damage and recovery was also examined 24 h and 72 h post-stroke using an antibody against laminin. Blood vessel density was decreased in the ischaemic core of both genotypes 24 h post-stroke and returned to pre-stroke levels only in Nox2 KO mice by 72 h. Overall, these results are the first to show that genetic Nox2 deletion merely delays the progression of neuronal loss after stroke but does not prevent it. Additionally, we show for the first time that Nox2 deletion increases re-vascularisation of the damaged brain by 72 h, which may be important in promoting endogenous brain repair mechanisms that rely on re-vascularisation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain / metabolism
  • Brain / pathology
  • Brain Ischemia / genetics*
  • Brain Ischemia / metabolism
  • Brain Ischemia / pathology
  • Disease Progression
  • Membrane Glycoproteins / genetics*
  • Membrane Glycoproteins / metabolism
  • Mice
  • Mice, Knockout
  • Microglia / metabolism
  • Microglia / pathology
  • NADPH Oxidase 2
  • NADPH Oxidases / genetics*
  • NADPH Oxidases / metabolism
  • Neovascularization, Physiologic / genetics*
  • Neurons / metabolism
  • Neurons / pathology
  • Reactive Oxygen Species / metabolism
  • Reperfusion Injury / genetics*
  • Reperfusion Injury / metabolism
  • Reperfusion Injury / pathology
  • Stroke / genetics*
  • Stroke / metabolism
  • Stroke / pathology

Substances

  • Membrane Glycoproteins
  • Reactive Oxygen Species
  • Cybb protein, mouse
  • NADPH Oxidase 2
  • NADPH Oxidases

Grants and funding

This work was supported by the National Heart Foundation Australia Research Grant-in-aid G07M3237 to GJD CLR, National Health and Medical Research Council Australia project grant #628767 to GJD CLR and Bethlehem Griffiths Research Foundaiton project grant to CLR GJD. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.