title: Inflammatory and hemodynamic changes in the cerebral microcirculation of aged rats after global cerebral ischemia and reperfusion.
abstract: 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.
authors.affiliation: College of Nursing, The University of Arizona, Tucson, Arizona 85721, USA. lritter@nursing.arizona.edu
authors.forename: Leslie
authors.initials: L
authors.lastname: Ritter
authors.forename: Janet
authors.initials: J
authors.lastname: Funk
authors.forename: Lori
authors.initials: L
authors.lastname: Schenkel
authors.forename: Alicia
authors.initials: A
authors.lastname: Tipton
authors.forename: Kate
authors.initials: K
authors.lastname: Downey
authors.forename: Jonathan
authors.initials: J
authors.lastname: Wilson
authors.forename: Bruce
authors.initials: B
authors.lastname: Coull
authors.forename: Paul
authors.initials: P
authors.lastname: McDonagh
mesh_terms: D000375:Aging / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D001921:Brain / Q000098:blood supply* / Q000378:metabolism* / Q000473:pathology; D039481:CD11b Antigen / Q000378:metabolism; D002448:Cell Adhesion; D002560:Cerebrovascular Circulation; D002561:Cerebrovascular Disorders / Q000378:metabolism* / Q000473:pathology; D006439:Hemodynamics; D007249:Inflammation / Q000378:metabolism / Q000473:pathology; D036904:Leukocyte Rolling; D007962:Leukocytes / Q000378:metabolism / Q000473:pathology; D008297:Male; D008833:Microcirculation / Q000378:metabolism / Q000473:pathology; D051381:Rats; D011916:Rats, Inbred F344; D015427:Reperfusion Injury / Q000378:metabolism* / Q000473:pathology
chemical_list: D039481:CD11b Antigen