期刊
JOURNAL OF NEUROSCIENCE
卷 27, 期 27, 页码 7083-7093出版社
SOC NEUROSCIENCE
DOI: 10.1523/JNEUROSCI.1645-07.2007
关键词
peroxynitrite; mice; ischemic preconditioning; hydroethidine; 3-nitrotyrosine; NADPH oxidase; focal cerebral ischemia; cranial window
资金
- NINDS NIH HHS [R01 NS034179, NS34179, R01 NS035806, NS35806, R37 NS034179] Funding Source: Medline
Cerebral ischemic preconditioning or tolerance is a powerful neuroprotective phenomenon by which a sublethal injurious stimulus renders the brain resistant to a subsequent damaging ischemic insult. We used lipopolysaccharide (LPS) as a preconditioning stimulus in a mouse model of middle cerebral artery occlusion (MCAO) to examine whether improvements in cerebrovascular function contribute to the protective effect. Administration of LPS 24 h before MCAO reduced the infarct by 68% and improved ischemic cerebral blood flow (CBF) by 114% in brain areas spared from infarction. In addition, LPS prevented the dysfunction in cerebrovascular regulation induced by MCAO, as demonstrated by normalization of the increase in CBF produced by neural activity, hypercapnia, or by the endothelium-dependent vasodilator acetylcholine. These beneficial effects of LPS were not observed in mice lacking inducible nitric oxide synthase (iNOS) or the nox2 subunit of the superoxide-producing enzyme NADPH oxidase. LPS increased reactive oxygen species and the peroxynitrite marker 3-nitrotyrosine in wild- type mice but not in nox2 nulls. The peroxynitrite decomposition catalyst 5,10,15,20-tetrakis( 4-sulfonatophenyl) porphyrinato iron (III) attenuated LPS-induced nitration and counteracted the beneficial effects of LPS on infarct volume, ischemic CBF, and vascular reactivity. Thus, LPS preserves neurovascular function and ameliorates CBF in regions of the ischemic territory at risk for infarction. This effect is mediated by peroxynitrite formed from iNOS-derived NO and nox2-derived superoxide. The data indicate that preservation of cerebrovascular function is an essential component of ischemic tolerance and suggest that combining neuroprotection and vasoprotection may be a valuable strategy for treating ischemic brain injury.
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