| Research Abstract |
Background and Purpose : The efficacy of hypothermic intervention for permanent focal ischemia had yet to be clarified. This study investigated the effect of a prolonged moderate or mild hypothermia on permanent focal ischemia in rats. Methods : Two permanent focal ischemia models in male Sprague-Dawley rats were used. Moderate (30℃, in experiment 1), or mild (33℃, in experiment 2) hypothermia was achieved at the time of the induction of focal ischemia, and was maintained for 2 h under general anesthesia. Thereafter, hypothermic condition was maintained using a cold room for a total of 24 h. The infarct volume and neurological function were analyzed for a maximum of 21 days and compared to that ofriormothermia group. Regional cerebral blood flow (rCBF) was monitored for 6 hours in the ischemic core and penumbra region.
Results : In experiment 1, the total infarct volume in the normothermic group was 368±59 mm3, in contrast, it was significantly smaller in the hypothermia group; 169 ± 33 mm^3 at 48 h (mean ± SEM, p< 0.05). In experiment 2, the infarct volume was 211 ± 19 mm^3 in the normothcrmia group and 88 ± 15 mm^3 in the hypothermia group at 21 day (p< 0.05). There were significant differences in neurological function from day 2 through 21 between the two groups. Mean rCBF in the penumbra region increased to a level more than 50 % baseline. Conclusions: Prolonged mild hypothermia suppressed the development of cerebral infarct and neurological deficit chronically after the induction of permanent focal ischemia. (Stroke, 32,1, 232-239,2001)
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