Nox2 oxidase activity accounts for the oxidative stress and vasomotor dysfunction in mouse cerebral arteries following ischemic stroke

De Silva, T. M., Brait, V. H., Drummond, G. R., Sobey, C. G. and Miller, A. A. (2011) Nox2 oxidase activity accounts for the oxidative stress and vasomotor dysfunction in mouse cerebral arteries following ischemic stroke. PLoS ONE, 6(12), e28393. (doi: 10.1371/journal.pone.0028393) (PMID:22164282) (PMCID:PMC3229592)

Abstract

Background and Purpose: Post-ischemic oxidative stress and vasomotor dysfunction in cerebral arteries may increase the likelihood of cognitive impairment and secondary stroke. However, the underlying mechanisms of post-stroke vascular abnormalities, as distinct from those causing primary brain injury, are poorly understood. We tested whether augmented superoxide-dependent dysfunction occurs in the mouse cerebral circulation following ischemia-reperfusion, and evaluated the role of Nox2 oxidase. Methods: Cerebral ischemia was induced in male C57Bl6/J wild-type (WT) and Nox2-deficient (Nox2-/-) mice by middle cerebral artery occlusion (MCAO; 0.5 h), followed by reperfusion (23.5 h). Superoxide production by MCA was measured by L-012-enhanced chemiluminescence. Nitric oxide (NO) function was assessed in cannulated and pressurized MCA via the vasoconstrictor response to Nω-nitro-L-arginine methyl ester (L-NAME; 100 µmol/L). Expression of Nox2, the nitration marker 3-nitrotyrosine, and leukocyte marker CD45 was assessed in cerebral arteries by Western blotting. Results: Following ischemia-reperfusion, superoxide production was markedly increased in the MCA of WT, but not Nox2-/- mice. In WT mice, L-NAME-induced constriction was reduced by ∼50% in ischemic MCA, whereas ischemia-reperfusion had no effect on responses to L-NAME in vessels from Nox2-/- mice. In ischemic MCA from WT mice, expression of Nox2 and 3-nitrotyrosine were ∼1.4-fold higher than in the contralateral MCA, or in ischemic or contralateral vessels from Nox2-/- mice. Vascular CD45 levels were unchanged by ischemia-reperfusion. Conclusions: Excessive superoxide production, impaired NO function and nitrosative stress occur in mouse cerebral arteries after ischemia-reperfusion. These abnormalities appear to be exclusively due to increased activity of vascular Nox2 oxidase.

• Item Type: Articles
• Additional Information: These studies were supported by grants from the National Health and Medical Research Council of Australia (NHMRC) (ID 350477 and 491133). TMD was the recipient of an Australian Postgraduate Award and VHB was the recipient of a Monash Graduate Scholarship. GRD and CGS are NHMRC Senior Research Fellows. AAM is a NHMRC Career Development Fellow.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Miller, Dr Alyson
• Authors: De Silva, T. M., Brait, V. H., Drummond, G. R., Sobey, C. G., and Miller, A. A.
• College/School: College of Medical Veterinary and Life Sciences > School of Cardiovascular & Metabolic Health
• Journal Name: PLoS ONE
• Publisher: Public Library of Science
• ISSN: 1932-6203
• ISSN (Online): 1932-6203
• Copyright Holders: copyright © 2011 De Silva et al.
• First Published: First published in PLoS ONE 6(12):e28393
• Publisher Policy: Reproduced under a Creative Commons License