| Title | A photothrombotic 'ring' model of rat stroke-in-evolution displaying putative penumbral inversion. | | Author(s) | Wester P, Watson BD, Prado R, Dietrich WD | | Institution | Department of Neurology, University of Miami, FL 33101. | | Source | Stroke 1995 Mar; 26(3):444-50. | | MeSH | Animals
Blood Platelets
Blood-Brain Barrier
Brain
Brain Ischemia
Carbon
Cerebral Arteries
Cerebral Infarction
Cerebrovascular Circulation
Cerebrovascular Disorders
Disease Models, Animal
Erythrosine
Intracranial Embolism and Thrombosis
Lasers
Male
Photochemistry
Rats
Rats, Wistar
Reproducibility of Results
| | Abstract | BACKGROUND AND PURPOSE: To facilitate reproducible and rigorous study of a tissue zone at risk of encroaching ischemic damage, we propose a new model in which the potentially compromised tissue lies within rather than perifocal to an ischemic locus. The perimeter of the "zone at risk" is defined by a photothrombotically produced cortical lesion in the shape of a toroid (or "ring").
METHODS: The exposed crania of erythrosin B-injected rats were irradiated with a 514.5-nm laser beam, configured as a 5-mm-diameter ring, to yield a ring-shaped lesion caused by photochemically induced platelet occlusion of cortical vasculature. Developing perfusion deficits in the interior region were revealed by carbon black infusion. Tissue damage and infarct volumes were assessed by light and electron microscopy, and blood-brain barrier integrity was assessed with Evans blue dye and horseradish peroxidase as tracers.
RESULTS: For rats injected with 17 mg/kg erythrosin B and irradiated for 2 minutes with a ring beam intensity of 0.92 W/cm2 (beam power of 65 mW), carbon black infusion at times up to 4 hours demonstrated a shallow cortical ring lesion encircling a fully patent zone at risk, which by 24 hours evinced an essentially complete perfusion deficit. At times up to 24 hours, the ring lesion was penetrated at the pial surface by distal branches of the middle cerebral and anterior cerebral arteries. Stereotaxically based histopathological assessment showed that by 24 hours the lesion spanned the cortical thickness. Lesion volume increased from 14.5 +/- 8.0 mm3 (mean +/- SD) (n = 8) to 46.2 +/- 15.6 mm3 (n = 8) between 4 and 24 hours after irradiation (P < .01), but the anteroposterior lesion diameter did not change significantly between 4 hours (6.00 +/- 1.03 mm; n = 9) and 24 hours (6.75 +/- 1.15 mm; n = 9).
CONCLUSIONS: The present model of slowly developing but inevitable cortical tissue death in a sequestered area should facilitate more precise observations of the evolution of tissue metabolic responses, from the impending onset of ischemia to the threshold of irreversible damage. This system may prove efficient for evaluating treatments intended to salvage a penumbral region. | | Language | eng | | Pub Type(s) | Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.
| | PubMed ID | 7886723 |
|
