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Neuroprotective effect of delayed moderate hypothermia after focal cerebral ischemia: an MRI study
R Kollmar1, W R Schäbitz, S Heiland
1Department of Neurology, University of Heidelberg, Heidelberg, Germany. Rainer_Kollmar@med.uni-heidelberg.de
Background And Purpose:
In contrast to early hypothermia, the effects of delayed hypothermia in focal cerebral ischemia have not been widely addressed. We examined the influence of delayed hypothermia on secondary ischemic injury, MRI lesion size, and neurological outcome after transient focal cerebral ischemia in a rat model.
Methods:
Rats (n=30) were subjected to transient middle cerebral artery occlusion (MCAO, 120 minutes) by use of the intraluminal filament model. Animals of the treatment group (n=12) were exposed to whole-body hypothermia of 33 degrees C for 5 hours starting 3 hours after MCAO, whereas the control group (n=18) was kept at 37 degrees C throughout the whole experiment. The normothermia- and hypothermia-treated animals were investigated daily by using the Menzies neurological score. Serial MRI was performed 1, 3, and 6 hours after MCAO and on days 1, 2, 3, and 5. After the final MRI scan, the rats were euthanized, and brain slices were stained by 2,3,5-triphenyltetrazolium chloride.
Results:
Delayed hypothermia resulted in a significant increase of survival rate and a significant improvement of the Menzies score. Moreover, a significant decrease in the extent of hyperintense volumes in T2-weighted scans and a reduction of cerebral edema as calculated from T2-weighted scans throughout the examination period were obvious. The extent of cerebral infarct volume and cerebral brain edema examined by MRI was consistent with 2,3,5-triphenyltetrazolium chloride staining.
Conclusions:
Our results suggest that even delayed postischemic hypothermia can reduce the extent of infarct volume and brain edema after transient focal cerebral ischemia.
Insights
Delayed hypothermia significantly improved survival and neurological scores in rats with focal cerebral ischemia. This treatment reduced infarct volume and brain edema, suggesting therapeutic potential.
Area of Science:
- Neuroscience
- Cerebrovascular Research
- Medical Imaging
Background:
- The impact of delayed hypothermia on focal cerebral ischemia is under-explored.
- Early hypothermia is established, but delayed interventions require investigation.
Purpose of the Study:
- To evaluate the efficacy of delayed hypothermia in mitigating secondary ischemic injury.
- To assess the effects of delayed hypothermia on MRI-measured lesion size and neurological outcomes in a rat model of transient focal cerebral ischemia.
Main Methods:
- Rats underwent transient middle cerebral artery occlusion (MCAO).
- The treatment group received whole-body hypothermia (33°C for 5 hours) starting 3 hours post-MCAO.
- Neurological scores (Menzies), serial MRI, and triphenyltetrazolium chloride staining were used for assessment.
Main Results:
- Delayed hypothermia significantly increased survival rates and improved neurological scores.
- MRI revealed a significant reduction in lesion volume and cerebral edema.
- Histological analysis confirmed reduced infarct volume and brain edema.
Conclusions:
- Delayed post-ischemic hypothermia demonstrates therapeutic potential.
- This intervention can effectively reduce infarct volume and brain edema following transient focal cerebral ischemia.