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Stroke Research and Treatment
Volume 2011 (2011), Article ID 764830, 6 pages
http://dx.doi.org/10.4061/2011/764830
Research Article

Persistent Penumbra in a Rabbit Stroke Model: Incidence and Histologic Characteristics

1Department of Pathology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
2Department of Radiology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
3Department of Biostatistics, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
4Division of Laboratory Animal Medicine, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA

Received 31 October 2010; Revised 4 April 2011; Accepted 20 April 2011

Academic Editor: David S. Liebeskind

Copyright © 2011 Leah J. Hennings et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Duration and extent of penumbra determine the window and brain volume in which interventions may save injured tissue after stroke. Understanding the penumbra in animals is necessary in order to design models that translate to effective clinical therapies. New Zealand white rabbits were embolized with aged autologous clot (n=23) or insoluble microspheres (n=21). To examine effects of treatment on penumbra, sphere-stroked animals were treated with 3 μm microbubbles plus ultrasound (n=19). Rabbits were euthanized at 4 or 24 hr. Infarct volume was measured following triphenyltetrazolium chloride (TTC) staining of brain sections. Penumbra was visualized using immunostaining of pimonidazole injected fifteen minutes prior to euthanasia. Potentially reversible penumbra was present in 14.3% stroked rabbits at 4 hours and 15.7% at 24 hours after embolic stroke and represented up to 35% of total lost tissue. Intervention at up to 24 hours may benefit a significant patient population.