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Inflammatory and Hemodynamic Changes in the Cerebral Microcirculation of Aged Rats after Global Cerebral Ischemia and Reperfusion
Author(s) -
Ritter Leslie,
Funk Janet,
Schenkel Lori,
Tipton Alicia,
Downey Kate,
Wilson Jonathan,
Coull Bruce,
Mcdonagh Paul
Publication year - 2008
Publication title -
microcirculation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.793
H-Index - 83
eISSN - 1549-8719
pISSN - 1073-9688
DOI - 10.1080/10739680701713840
Subject(s) - medicine , microcirculation , ischemia , hemodynamics , middle cerebral artery , intravital microscopy , anesthesia , cerebral blood flow , cardiology
Effects of aging on inflammation and blood flow in the brain are unclear. Young (three to six months) and aged (19–22 months) male Brown Norway Fisher rats were used to compare (i) leukocyte function in nonischemic conditions and (ii) leukocyte function and hemodynamic changes after ischemia‐reperfusion (I‐R). In nonischemic studies, polymorphonuclear (PMN) CD11b expression and reactive oxygen species (ROS) production were measured with flow cytometry and PMN chemotaxis was measured with a Boyden chamber (+/‐fMLP). In I‐R studies, ischemia was induced by bilateral carotid artery occlusion and hypotension (20 minutes). During early reperfusion (30 minutes), leukocyte adhesion and rolling and blood‐shear rates were measured using fluorescence microscopy. During late reperfusion (48 hours), mortality, neurological function, and leukocyte infiltration were measured. Stimulated PMN chemotaxis was increased in nonischemic aged rats (p < 0.05). In early reperfusion, there was a significant increase in leukocyte rolling and adhesion in the cerebral microcirculation and a significant decrease in shear rate in aged rats, compared to the young (p < 0.05). During late reperfusion, neurologic function was worse in aged vs. young rats (p < 0.05). These findings suggest that increased intravascular PMN adhesion and vascular dysfunction may contribute to poor neurologic outcome after cerebral I‐R in the aged brain.