【摘要】 目的研究脑缺血预处理对Fas、Fas L、Caspase-3蛋白在大鼠脑缺血再灌注脑梗死组织中变化的影响及其作用机制。方法按照体重将SD大鼠随机分为3组:模型Ⅰ组、模型Ⅱ组和假手术组,每组30只。模型Ⅰ组采用ZeaLonga’大脑中动脉线栓法制备;模型Ⅱ组给予右侧颈内动脉阻断血流10 min完成预缺血;3 d后,与模型Ⅰ组同用大脑中动脉线栓法建立脑缺血再灌注模型;假手术组大鼠仅需分离右颈总动脉。术后,在6,12,24,48,72 h这5个时间点评估各组大鼠的神经行为,测定脑梗死体积,以免疫组化法测定大鼠脑组织的Fas、Fas配体(Fas L)及Caspase-3蛋白水平,用缺口末端标记(TUNEL)法检测大鼠脑组织的神经细胞凋亡率。结果术后24 h,模型Ⅰ组、模型Ⅱ组和假手术组的神经功能缺损评分分别为(2.8±0.8),(1.8±0.8),0分;这3组的脑组织Fas蛋白阳性细胞表达分别为(35.67±2.16)%,(22.83±1.71)%,(14.17±2.32)%;这3组的脑组织Fas L蛋白阳性细胞表达分别为(36.50±1.38)%,(22.67±2.50)%,(13.33±1.21)%;这3组的脑组织Caspase-3蛋白阳性细胞表达分别为(37.33±1.03)%,(23.17±1.47)%,(11.33±1.37)%;这3组的脑组织神经细胞凋亡率分别为(40.58±1.72)%,(23.25±1.13)%,(11.75±1.37)%。大鼠在术后神经功能缺损评分及Fas、Fas L、Caspase-3蛋白和凋亡细胞数的表达,模型Ⅱ组均低于模型Ⅰ组;同时2个模型组均高于假手术组,差异有统计学意义(均P<0.05)。结论脑缺血预处理可下调脑缺血再灌注大鼠脑组织Fas、Fas L、Caspase-3蛋白的表达水平,抑制神经元的凋亡;抑制Fas、Fas L信号通路可能是脑缺血预处理诱导的脑保护机制之一。更多还原

【Abstract】 Objective To study effects of cerebral ischemic preconditioning on the changes of Fas,Fas L,Caspase- 3 proteins in infarction tissue after cerebral ischemia reperfusion of rats and to explore its mechanism. Methods The rats were randomly divided into three groups as follows: modelⅠgroup,modelⅡgroup and the sham operated group. Each group had thirty rats. The rats in model Ⅰ were prepared by Zea- Longa’middle cerebral artery occlusion. The right internal carotid artery of rats in modelⅡ group was blocked transiently 10 minutes at one time. After 3 days,the middle cerebral artery occlusion of rat in modelⅡ group was used to establish focal cerebral ischemia reperfusion injury model according to the model Ⅰ group. The sham operated group only isolated carotid artery. The neural behavior of rats was evaluated and the volume of cerebral infarction was detected after operation at 6,12,24,48,72 h( each group had six rats). The expressions of Fas,Fas L and Caspase- 3 protein of rats at different time points after operation were observed by immunohistochemical method. The apoptosis rate of nerve cells were detected by Td T- mediated d UTP nick- end labeling( TUNEL) method. Results At the time of 24 h after operated,the neural function defect point in model Ⅰ group,model Ⅱ group and sham operated group of rats were( 2. 8 ± 0. 8),( 1. 8 ± 0. 8),0 point. The expression of Fas protein positive cells in rats’ brain tissue were( 35. 67 ± 2. 16) %,( 22. 83 ± 1. 71) %,( 14. 17 ±2. 32) % in that three groups. The expression of Fas L protein positive cells in rats’ brain tissue were( 36. 50 ± 1. 38) %,( 22. 67 ± 2. 50) %,( 13. 33 ± 1. 21) % in that three groups. The expression of Caspase- 3protein positive cells in rats’ brain tissue were( 37. 33 ± 1. 03) %,( 23. 17 ± 1. 47) %,( 11. 33 ± 1. 37) %. The apoptotic rate in brain tissue of rats were( 40. 58 ± 1. 72) %,( 23. 25 ± 1. 13) %,( 11. 75 ± 1. 37) % in that three groups. Compared with modelⅠgroup,the neural function defect point of rats or the expression rat of Fas,Fas L,Caspase- 3 protein and the number of apoptotic nerve cells in modelⅡgroup at the same time all decreased; but the two groups were significantly higher than the sham operated group,( all P < 0. 05). Conclusion Cerebral ischemic preconditioning can reduce the expression of Fas,Fas L and Caspase- 3 proteins. Negative regulation of Fas and Fas L pathway after ischemic preconditioning may be an important endogenous mechanism of the resistance to damage.更多还原