Study On Hypothermic Treatment Window After Acute Subarachnoid Hemorrhage In Rats

Objective: to study the effect of cerebral pathology, metabolism, cerebral bloodflow, etc after acute subarachnoid hemorrhage in rats applying microdialysis, LaserDoppler Flowmetry and electron microscope technique and the time window of thehypothemic treatment.Methods: 50 rats are divided into 5 groups: control group,normothermic SAH group,hypothermic SAH 2h group, hypothermia SAH 4h group, hypothermia SAH 6h group.Introduce rat animal model by two stages blood injection. Hypothermia treats ratmodel immediately when second blood injection is finished,using ice bag all throughthe rat body. The temperature of hopythermia groups respectively is controlledbetween 31℃-33℃. The other two groups keep up with normal temperature. Measureof blood flow of rat cortical layer: Fix the laszer Doppler transducer to micropropeller of the stereotaxic apparatus,Stick the probe of the micro propeller to localdistrictin bone window lightly, where there is no blood vessel. The relationshipbetween the intensity of instrument signal and the flow of red blood cell inhemispheroid biological tissue which is lmm blow laszer transducer, and determinethe local blood flow when it is in 1,3,5 days. Morphology observation: the braintissue of each group is examined by pathology and electron microscope.Observe thechange of brain tissue after subarachnoid hemorrhage. The biological detection ofmicrodialysis: Insert the microdialysis tube in hippocampus which is injected blood.Assemble the dialysate, analyze the biological signal of lactic acid,glucose, pyruvateacid,L/P by CMAmicrodislysis biological analysator.Result:1.The animal model proves successful according to SAH distribution, LDF monitoring and the physiological index change.2. The result of microdislysis: change of Glu and Pyru: control group＞H6＞H4＞H2and common temperature group; Lac and L/P: H2 and common temperaturegroup＞H4＞CONTROL GROUP＞H6;3. The result of monitoring of brain blood flow: The brain blood flow decreasesgreatly after second injection of blood. The contrast has no statistically significantbetween hypothermia groups and common temperature group. There is notobviously change in control group.4. The result of electron microscope: The endothelial cell of arteria basilaris incommon temperature group damages serviously, the degree of injury differs in eachofhypothermia group.The H6 group seems most slightly injuried in all groups.Conclusion:The H6 group is superior to other groups in oxygen consumption ,cellenergy metabolism and pathology, electron microscope aspect according to the studyof hypothermia treat in different time window in super acute stage of subarachnoidhemorrhage.