Transient hypothermia reduces focal ischemic brain injury in the rat.
The effect of transient hypothermia on focal cerebral ischemia was evaluated using a rat model of permanent middle cerebral artery (MCA) occlusion. MCA occlusion was performed on 10 rats at a temporalis muscle temperature of 24 degrees C (hypothermic group) and on 10 rats at 36 degrees C (normothermic group). Rats in the hypothermic group were maintained at 24 degrees C for 1 hour after MCA occlusion and then allowed to rewarm to 36 degrees C over the next 2 hours. Animals in both groups were killed 24 hours after MCA occlusion. Cerebral infarcts were visualized by staining of coronal brain sections with 2,3,5-triphenyltetrazolium chloride. Normothermic rats displayed an average infarct volume of 233.1 +/- 13.2 mm3 (standard error of the mean), whereas hypothermic rats had an average infarct volume of 166.2 +/- 22.8 mm3 (P less than 0.01). Expressed as a percentage of the volume of the right hemisphere, the normothermic group had an infarct volume of 22.1 +/- 1.5% and the hypothermic group an infarct volume of 16.0 +/- 2.2% (P less than 0.05). These results demonstrate that transient hypothermia to a temporalis muscle temperature of 24 degrees C significantly reduces subsequent infarct size in an experimental model of permanent arterial occlusion.
Onesti
S T
ST
Department of Neurological Surgery, Columbia University College of Physicians and Surgeons, New York, New York.
Baker
C J
CJ
Sun
P P
PP
Solomon
R A
RA
D000818:Animals; D002544:Cerebral Infarction / Q000473:pathology* / Q000503:physiopathology; D007036:Hypothermia, Induced; D002546:Ischemic Attack, Transient / Q000473:pathology* / Q000503:physiopathology; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR