C57black/6小鼠全脑缺血模型Fas-L和Caspase-3的表达

The Expression of Fas-L and Caspase-3 in C57black/6 Mice after Global Cerebral Ischemia

目的应用C57black/6小鼠制备全脑缺血模型,观察脑缺血后大脑皮质、丘脑、下丘脑杏仁核部位Fas-L和Caspase-3基因的表达。方法双侧颈总动脉夹闭(bilateral common carotid artery occlusion,BCCAO)15 min,造成全脑缺血,24 h后取脑组织进行Fas-L和Caspase-3免疫组织化学染色。结果Fas-L阳性细胞广泛分布在大脑皮质、丘脑、下丘脑、杏仁核。除丘脑外,缺血组其他部位Fas-L阳性神经元细胞密度均显著高于假手术组(P<0.01);缺血组各区域细胞染色灰度值均显著低于假手术组(P<0.01)。Caspase-3阳性细胞在大脑皮质、丘脑、下丘脑均有表达,缺血组各区域阳性神经元细胞密度均显著高于假手术组(P<0.05,P<0.01);缺血组各区域细胞染色灰度值均显著低于假手术组(P<0.01)。结论双侧颈总动脉夹闭法可复制C57black/6小鼠全脑缺血模型,缺血再灌注24 h后,Fas-L和Caspase-3基因在多个区域表达增加。提示该全脑缺血模型中,神经元死亡信号传导需要Caspases基因家族成员表达的加强,且存在缺血后神经元死亡信号传导的外源性通路。

Objective C57black/6 mice are increasingly used for experimental stroke research while how the neuron death is induced and what the pathway of dead signal transduction is after ischemia in this model are still unknown. Methods In this study global cerebral ischemia was induced by bilateral common carotid artery occlusion （BCCAO） in C57black6 mice. C57black/6 mice were subjected to 15 min occlusion followed by reperfusion for 24 h. Fas-L and Caspase-3 immunohistochemical staining of brain tissue were performed. Results Fas-L-positive neurons were distributed in retrosplenial agranular cortex（RSA）, piriform cortex （Pir）, ventral posterolateral thalamic nucleus/ventral posteromedial thalamic nucleus（VPL/VPM）, arcuate hypothalamic nucleus （Arc） and medial amygdaloid nucleus, posteroventral （MePV） areas and the cytoplasm was stained. There were more positive neurons in the ischemia group than in the sham-surgery group（P〈0.01） for all observed areas except VPL/VPM. And the positive neurons were more darkly stained in the ischemia group（P〈0.01）. Caspase-3-positive neurons were distributed in RSA, Pir, VPL/VPM and MePV areas. The Caspase-3-positive neurons were less in number and lightly stained compared with Fas-L- positive neurons. Also there were more Caspase-3-positive neurons in the ischemia group than in the sham-surgery group（P% 0. 05 , P%0. 01）. The positive neurons were more darkly stained in the ischemia group（P%0.01）. Conclusion These results showed that C57black/6 mice model of global ischemia can induce extensive expression of Fas-L and Caspase-3 in brain,indicating that members of Caspases family were involved in the pathway of neuron death signal transduction and there was exogenetic pathway during this process for this kind of global ischemia model.