【摘要】 目的　揭示脑缺血后短T1信号产生的病理基础。方法　将 56只健康雄性Wistar大鼠按不同的大脑中动脉闭塞时间组 (T0 =0min ,T1 a =15min ,T1 b =3 0min ,T1 c =60min ,T1 d =永久性闭塞 )制备局灶性脑缺血模型 ,动态观察短T1信号出现的时间、部位 ,并行光学显微镜和电子显微镜检查。结果　总计 46只存活模型可列入统计结果。T0 组 (7只 )中无短T1信号出现 ;T1 a组 (13只 )中 7只出现短T1信号 ;T1 b组 (12只 )中 8只出现短T1信号 ;T1 c组 (7只 )与T1 d组 (7只 )中全部出现短T1信号。短T1信号出现阳性者在不同缺血时间组之间差异有显著性意义 (χ2 =2 9.3 2 8,P <0 .0 5) ;短T1信号区域的组织学检查可见出血、吞噬脂肪的巨噬细胞的脂质沉积和蛋白质变性、髓鞘破坏等 ;皮质区短T1信号出现时间早 ,主要与出血有关 ,基底节区短T1信号主要与脂质沉积有关 ,出现时间晚。结论　不同时间、部位出现的短T1信号产生的病理基础不同 ;短T1信号的产生主要与缺血 再灌注损伤程度有关更多还原

【Abstract】 Objective To verify the pathol ogical basis of high signal intensity on T 1 weighted image after brain ischemia by using the rat model. Methods Fifty-six male Wistar rats, weighing 250 to 300 g, were used for the model of middle cerebral artery occlusion(MCAO). 46 rats model were counted in the results. They were divided into two groups randomly, experimental group (T 1, n =39) and control group (T 0, n =7). Experimental group was further divided into 4 subgroups: 15 minute’s MCAO (T 1-a, n =13), 30 minute’s MCAO (T 1-b, n =12), 60 minute’s MCAO (T 1-c, n =7), and permanent MCAO (T 1-d, n =7). Intraluminal filament technique was used with the method modified by Zea-Longa. Follow-up MRI was applied to observe the time and the position of short T 1 signal. H & E staining and electronic microscope were applied to observe the pathological changes in the position of short T 1 signal. Results In T 0 group ( n = 7), no short T 1 signal was observed in bilateral cerebral hemispheres. In T 1-a subgroup ( n =13), short T 1 signal was observed in 7 rats at the 14 th day. In T 1-b subgroup ( n =12), short T 1 signal was observed in the ischemic side in 8 rats. All of the rats in T 1-c subgroup ( n =7) and T 1-d subgroup ( n =7) were observed to have short T 1 signal. The histological changes of short T 1 signal were hemorrhage, lipid-laden macrophage, denatured protein, and myelinolysis. Earlier short T 1 signal in cortical region was mainly related with hemorrhage, short T 1 signal in the basal ganglia appeared at a later stage, which was induced by lipid-laden macrophages. The occurrence of short T 1 signal was prominently different in the time of MCAO (χ 2=29.328, P <0.05). Conclusion The pathological basis of short T 1 signal was different at various time of MCAO and in different positions of the ischemic brain tissue. The degree of ischemia-reperfusion induced injury was highly correlated with the occurrence of short T 1 signal.更多还原