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Open Access Highly Accessed Research article

The neuroprotective effect of post ischemic brief mild hypothermic treatment correlates with apoptosis, but not with gliosis in endothelin-1 treated rats

Tine Zgavc1, An-Gaëlle Ceulemans1, Said Hachimi-Idrissi2, Ron Kooijman3, Sophie Sarre1* and Yvette Michotte1

Author Affiliations

1 Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neuroscience, Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, Belgium

2 Critical Care Department and Cerebral Resuscitation Research Group, Center for Neuroscience, Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, Belgium

3 Department of Pharmacology, Center for Neuroscience, Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, Belgium

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BMC Neuroscience 2012, 13:105  doi:10.1186/1471-2202-13-105

Published: 26 August 2012

Abstract

Background

Stroke remains one of the most common diseases with a serious impact on quality of life but few effective treatments exist. Mild hypothermia (33°C) is a promising neuroprotective therapy in stroke management. This study investigated whether a delayed short mild hypothermic treatment is still beneficial as neuroprotective strategy in the endothelin-1 (Et-1) rat model for a transient focal cerebral ischemia. Two hours of mild hypothermia (33°C) was induced 20, 60 or 120 minutes after Et-1 infusion. During the experiment the cerebral blood flow (CBF) was measured via Laser Doppler Flowmetry in the striatum, which represents the core of the infarct. Functional outcome and infarct volume were assessed 24 hours after the insult. In this sub-acute phase following stroke induction, the effects of the hypothermic treatment on apoptosis, phagocytosis and astrogliosis were assessed as well. Apoptosis was determined using caspase-3 immunohistochemistry, phagocytic cells were visualized by CD-68 expression and astrogliosis was studied by glial fibrillary acidic protein (GFAP) staining.

Results

Cooling could be postponed up to 1 hour after the onset of the insult without losing its positive effects on neurological deficit and infarct volume. These results correlated with the caspase-3 staining. In contrast, the increased CD-68 expression post-stroke was reduced in the core of the insult with all treatment protocols. Hypothermia also reduced the increased levels of GFAP staining, even when it was delayed up to 2 hours after the insult. The study confirmed that the induction of the hypothermia treatment in the Et-1 model does not affect the CBF.

Conclusions

These data indicate that in the Et-1 rat model, a short mild hypothermic treatment delayed for 1 hour is still neuroprotective and correlates with apoptosis. At the same time, hypothermia also establishes a lasting inhibitory effect on the activation of astrogliosis.

Keywords:
Hypothermia; Cerebral ischemia; Endothelin-1; Caspase-3; Gliosis; Phagocytosis