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目的:通过观察大鼠实验性出血性脑水肿的MRI动态变化,分析亚低温对脑水肿的干预效果。方法:实验于2004-03/2005-04在徐州医学院神经生物学教研室和徐州医学院附属医院核磁共振室完成。选用22只健康SD雄性大鼠,按完全随机设计的方法分为3组,亚低温组、对照组、假手术组分别为9,10和3只。亚低温组与对照组组大鼠苍白球注射胶原酶造成脑出血模型,假手术组不注射药物。亚低温组大鼠随即放至装有冰袋的纸箱中降温,使肛温维持在(32±1)℃;对照组及假手术组使体温维持在(37±1)℃。通过观察MRI[T1,T2,FLAIR(液体衰减反转恢复序列)]的相关指标计算各组大鼠的血肿吸收率[血肿吸收率=(出血后1d的血肿体积-出血后7d的血肿体积)/出血后1d的血肿体积×100%]、水肿吸收率(计算方法同血肿吸收率)、信号强度比(反应脑水肿的相对含水量,T2WI,FLAIR序列信号强度比越高,含水量越多)及信号强度比相对变化率(计算方法同血肿吸收率)。结果:因死亡及MRI显示血肿过小等原因,最后进入结果分析亚低温组、对照组、假手术组分别为6,6和3只。①亚低温组大鼠的血肿吸收率显著高于对照组[(68.27±6.14)%,(61.19±4.19)%(P<0.05)]。②亚低温组大鼠的水肿吸收率显著高于对照组[(53.88±9.45)%,(40.75±5.01)%(P<0.01)]。③假手术组大鼠左右侧大脑半球各序列信号强度相比,差异无显著性意义(P>0.05)。各个时间点亚低温组大鼠T2WI,FLAIR序列的信号强度比均明显低于对照组(P<0.01)。亚低温组大鼠T2WI,FLAIR序列的信号强度比相对变化率显著高于对照组(t=5.038,4.629,P<0.01)。结论:亚低温可促进大鼠脑出血模型脑内血肿及水肿的吸收,可减低T2WI,FLAIR序列水肿区的信号强度,提示亚低温可减少水肿区的含水量。
Objective: To observe the effect of mild hypothermia on cerebral edema by observing the dynamic changes of MRI in experimental hemorrhagic brain edema in rats. METHODS: The experiment was performed at the Department of Neurobiology, Xuzhou Medical College and the Nuclear Magnetic Resonance Laboratory, Xuzhou Medical College Hospital from March 2004 to April 2005. Twenty-two healthy male Sprague Dawley rats were randomly divided into three groups according to randomized design. The hypothermia group, control group and sham operation group were 9, 10 and 3, respectively. The model of intracerebral hemorrhage was induced by the injection of collagenase into the globus pallidus in the hypothermia group and the control group, but not in the sham operation group. Rats in the mild hypothermia group were then placed in a carton with ice packs to cool down, keeping the rectal temperature at 32 ± 1 ° C. The body temperature of the control group and the sham operation group was maintained at 37 ± 1 ° C. The hematoma absorption rate of each group of rats was calculated by observing the related indexes of MRI [T1, T2, FLAIR] [hematoma absorption rate = (hematoma volume at 1 day after hemorrhage - hematoma volume at 7 days after hemorrhage) / Volume of hematoma on day 1 after hemorrhage × 100%], edema absorption rate (calculated as hematoma absorption rate), signal intensity ratio (relative water content of reaction brain edema, higher signal intensity ratio of T2WI and FLAIR sequences, ) And the relative rate of change of signal intensity (calculation method with the hematoma absorption rate). Results: Because of death and MRI showed that the hematoma is too small and so on, the final entry into the analysis of the results of mild hypothermia, control group, sham group were 6, 6 and 3. ① The rate of hematoma absorption in the mild hypothermia group was significantly higher than that in the control group (68.27 ± 6.14% vs 61.19 ± 4.19%, P <0.05). ② The edema absorption rate in the mild hypothermia group was significantly higher than that in the control group [(53.88 ± 9.45)%, (40.75 ± 5.01)%, P <0.01]. (3) There was no significant difference in the signal intensities between the left and right cerebral hemispheres in the sham operation group (P> 0.05). The signal intensity ratios of T2WI and FLAIR sequences in the mild hypothermia group at each time point were significantly lower than those in the control group (P <0.01). The relative change rate of T2WI and FLAIR sequences in the mild hypothermia group was significantly higher than that in the control group (t = 5.038, 4.629, P <0.01). Conclusion: Mild hypothermia can promote the intracerebral hematoma and edema absorption in ICH rat model, which can reduce the signal intensity of T2WI and FLAIR sequence edema region, suggesting that mild hypothermia can reduce the water content in edema area.