Hyperthermia induced after recirculation triggers chronic neurodegeneration in the penumbra zone of focal ischemia in the rat brain

Hyperthermia induced after recirculation triggers chronic neurodegeneration in the penumbra zone of focal ischemia in the rat brain

Author Favero-Filho, Luiz Antonio Autor UNIFESP Google Scholar
Borges, Andrea Aurélio Autor UNIFESP Google Scholar
Grassl, Christian Autor UNIFESP Google Scholar
Lopes, Antonio Carlos Autor UNIFESP Google Scholar
Sinigaglia-Coimbra, Rita Autor UNIFESP Google Scholar
Coimbra, Cicero Galli Autor UNIFESP Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Abstract Chronic neurodegenerative processes have been identified in the rat forebrain after prolonged survival following hyperthermia (HT) initiated a few hours after transient global ischemia. Since transient global ischemia and ischemic penumbra share pathophysiological similarities, this study addressed the effects of HT induced after recirculation of focal brain ischemia on infarct size during long survival times. Adult male Wistar rats underwent intra-luminal occlusion of the left middle cerebral artery for 60 min followed by HT (39.0-39.5°C) or normothermia. Control procedures included none and sham surgery with and without HT, and middle cerebral artery occlusion alone. Part I: 6-h HT induced at recirculation. Part II: 2-h HT induced at 2-, 6-, or 24-h recirculation. Part III: 2-h HT initiated at recirculation or 6-h HT initiated at 2-, 6- or 24-h recirculation. Survival periods were 7 days, 2 or 6 months. The effects of post-ischemic HT on cortex and striatum were evaluated histopathologically by measuring the area of remaining tissue in the infarcted hemisphere at -0.30 mm from bregma. Six-hour HT initiated from 6-h recirculation caused a significant decrease in the remaining cortical tissue between 7-day (N = 8) and 2-month (N = 8) survivals (98.46 ± 1.14 to 73.62 ± 8.99%, respectively). When induced from 24-h recirculation, 6-h HT caused a significant reduction of the remaining cortical tissue between 2- (N = 8) and 6-month (N = 9) survivals (94.97 ± 5.02 vs 63.26 ± 11.97%, respectively). These data indicate that post-ischemic HT triggers chronic neurodegenerative processes in ischemic penumbra, suggesting that similar fever-triggered effects may annul the benefit of early recirculation in stroke patients over the long-term.
Keywords Hyperthermia
Ischemic penumbra
Rat focal ischemia
Language English
Date 2008-11-01
Published in Brazilian Journal of Medical and Biological Research. Associação Brasileira de Divulgação Científica, v. 41, n. 11, p. 1029-1036, 2008.
ISSN 0100-879X (Sherpa/Romeo, impact factor)
Publisher Associação Brasileira de Divulgação Científica
Extent 1029-1036
Origin http://dx.doi.org/10.1590/S0100-879X2008001100014
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000261960500014
SciELO ID S0100-879X2008001100014 (statistics in SciELO)
URI http://repositorio.unifesp.br/handle/11600/4613

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