Effects of mild hypothermia on cerebral blood flow, infarct size and neurological outcome after a transient focal cerebral ischemia in rats

Tine Zgavc, An-Gaelle Ceulemans, Said Hachimi-Idrissi, Ron Kooijman, Sophie Sarre, Yvette Michotte

Research output: Chapter in Book/Report/Conference proceedingMeeting abstract (Book)

Abstract

Background: Hypothermia is a proven neuroprotective therapy after an ischemic insult. However, the time frame in which mild hypothermia is still beneficial remains unanswered. The aim of this study is to evaluate the therapeutic window for mild hypothermia in the endothelin-1 (Et-1) rat model for focal cerebral ischemia and to investigate whether hypothermia exerts an effect on cerebral blood flow. We compared the neuroprotective effects of hypothermia started 20 min after the ischemic insult versus hypothermia started after 60 or 120 min. Methods: Et-1, a potent vasoconstrictor, was infused near the middle cerebral artery of male Wistar rats. Brain temperature was kept either under normothermic (37°C) or under hypothermic conditions (33°C) for 2h starting with a delay of 20, 60 or 120 min after the insult. The effects on neurological outcome (neurological deficit score) and infarct size were evaluated 24h after the insult. The blood flow was measured during the experiment via Laser Doppler Flowmetry in the striatum, which represents the core of the infarct. Results: Neurological outcome improved when hypothermia was initiated 20 or 60 min after the insult compared to the normothermic group, which was reflected in the infarct volume where a decrease of 45% and 35% respectively was seen. Application of hypothermia after 120 min did not affect neurological outcome nor infarct volume. Infusion of Et-1 resulted in a decrease in blood flow by approximately 90% for 20 min, followed by an increase of 200% compared to basal values. After this reperfusion phase, the blood flow stabilized at 70% of basal values. Hypothermic treatment, started 20 min after the Et-1 administration, resulted in a less pronounced increase in blood flow during the reperfusion phase. Conclusion: These findings indicate that in the Et-1 model, hypothermia influences the blood flow and remains neuroprotective even when the initiation of the treatment is delayed for 60 min after the insult.
Original languageEnglish
Title of host publication"19th European Stroke Conference"
Publication statusPublished - 25 May 2010
EventFinds and Results from the Swedish Cyprus Expedition: A Gender Perspective at the Medelhavsmuseet - Stockholm, Sweden
Duration: 21 Sep 200925 Sep 2009

Publication series

Name"19th European Stroke Conference"

Conference

ConferenceFinds and Results from the Swedish Cyprus Expedition: A Gender Perspective at the Medelhavsmuseet
Country/TerritorySweden
CityStockholm
Period21/09/0925/09/09

Keywords

  • Stroke
  • Hypothermia

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