C3a receptor modulation of granulocyte infiltration after murine focal cerebral ischemia is reperfusion dependent.

Department

Neurosurgery

Document Type

Article

Abstract

The complement anaphylatoxin C3a contributes to injury after cerebral ischemia in mice. This study assesses the effect of C3a receptor antagonist (C3aRA) on leukocyte infiltration into the ischemic zone. Transient or permanent middle cerebral artery occlusion (MCAO) was induced in wild-type C57Bl/6 mice. Intraperitoneal C3aRA or vehicle was administered 45 mins before or 1 h after occlusion. Twenty-four hours after occlusion, we harvested brain tissue and purified inflammatory cells using flow cytometry. Soluble intercellular adhesion molecule (ICAM)-1 protein levels were assessed using enzyme-linked immunosorbent assays, and ICAM-1 and C3a receptor (C3aR) expression was confirmed via immunohistochemistry. In the transient MCAO model, animals receiving C3aRA showed smaller strokes, less upregulation of C3aR-positive granulocytes, and less ICAM-1 protein on endothelial cells than vehicle-treated animals; no significant differences in other inflammatory cell populations were observed. C3a receptor antagonist-treated and vehicle-treated animals showed no differences in stroke volume or inflammatory cell populations after permanent MCAO. These data suggest that blocking the binding of C3a to C3aR modulates tissue injury in reperfused stroke by inhibiting the recruitment of neutrophils to the ischemic zone. It further establishes antagonism of the C3a anaphylatoxin as a promising strategy for ameliorating injury after ischemia/reperfusion.

Medical Subject Headings

Anaphylatoxins; Animals; Arginine; Benzhydryl Compounds; Brain; Brain Ischemia; Complement C3a; Disease Models, Animal; Flow Cytometry; Granulocytes; Infarction, Middle Cerebral Artery; Intercellular Adhesion Molecule-1; Male; Mice; Mice, Inbred C57BL; Neuroprotective Agents; Receptors, Complement; Reperfusion Injury

Publication Date

5-1-2008

Publication Title

Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism

ISSN

0271-678X

Volume

28

Issue

5

First Page

1048

Last Page

1058

PubMed ID

18197178

Digital Object Identifier (DOI)

10.1038/sj.jcbfm.9600608

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