Study Of The Rewarming Methods Of Hypothermia In Rats With Cerebral Ischemia

Objective: The goal of this study was to evaluate the differential effects of three re-warming methods of hypothermia in rats with cerebral ischemia.Methods: Thirty Wistar rats were randomly assigned to three groups as follows: passive re-warming group (control), active surface-re-warming group (shining) and active internal re-warming group (intragaseric administration), and each group is ten. The focal cerebral ischemic model was made with the intraluminal filament. After 6h in room temperature, all the rats were introduced into hypothermia (rectal temperature, 32.0 ± 1 ℃) for 24h before re-warming. Intercerebral pressure (ICP), blood pressure (BP), heart beating (Hb), and rectal temperature (RT) were assessed and compared during re-warming. After re-warming, neurological grading scale was compared. All the rats were sacrificed with overanaesthetia and infarction size and mortality were compared.Results: After 4h of re-warming, rectal temperature in active internal re-warming group was obviously lower than that of active surface-re-warming group and the BP was obviously increased (P<0.05) . After 6h of re-warming, BP in active internal re-warming group was obviously higher than that of active surface-re-warming group (P<0.05) . ICP in all the three groups increased obviously and in active surface-re-warming group was obviously lower than that of passive re-warming group after 4h of re-warming, and that of active internal re-warming group was obviously higher than that of passive re-warming group after 6h of re-warming. At the end of re-warming, the time to reach target temperature, Infarction size, Neurological grading scale, ICP and BP of active internal re-warming group were obviously higher than active surface-re-warming group (P<0.05) . Mortality in active internal re-warming group was obviously higher than that of other two groups (P<0.05) .Conclusion: ICP in all the three groups increased obviously, but heart rate did not changed obviously during re-warming. Intragaseric administration was not an advisable method. Shining group and passive group got the resembling effect.