小鼠全脑缺血模型海马区Bcl-2和Bax的表达

背景由C57black/6小鼠制成的全脑缺血模型在实验性脑缺血的研究中使用在明显增加,目前需要对这种模型的神经元损伤死亡在分子生物学方面的改变进行全面深入的研究,此项研究正是观察两种与缺血神经元死亡密切相关基因的表达水平.目的在小鼠全脑缺血模型上观察缺血后海马区Bcl-2和Bax的表达,在蛋白分子表达水平对该模型进行研究,为这种模型在今后脑缺血研究中的应用提供实验依据.设计以实验动物为研究对象,随机对照前瞻性研究.单位一所大学生理学和病理解剖学教研室.对象实验于2002-11/2003-05在首都医科大学生理系完成.选择C57black/6小鼠12只,随机分为假手术组和对照组,每组6只.干预双侧颈总动脉夹闭15 min诱发全脑缺血模型,24 h后取脑组织.全脑缺血后应用免疫组织化学染色,观察海马Bcl-2和Bax的表达水平.主要观察指标海马Bcl-2和Bax的表达水平.结果缺血组海马CA1区Bax阳性反应神经元数目为(57.3±2.9个)个,假手术组Bax阳性细胞数目为(17.2±1.3)个,两组比较,差异有显著性意义(t=30.91,P＜0.05).缺血组CA3区和齿状回Bcl-2阳性反应神经元数目为(43.9±1.1)个,假手术组Bcl-2阳性细胞数目为(28.6±1.7)个,两组比较,差异有显著性意义(t=18.51,P＜0.05).阳性着色区灰度值测定结果显示缺血组海马CA1区Bax阳性细胞染色灰度值为90.45±5.23,假手术组Bax阳性细胞染色灰度值为168.39±4.55,两组比较,差异有显著性意义(t=27.54,P＜0.05);缺血组CA3区和齿状回Bcl-2阳性细胞染色灰度值为113.10±4.20,假手术组Bcl-2阳性细胞染色灰度值为157.25±7.68,两组比较,差异有显著性意义(t=12.35,P＜0.05).结论小鼠全脑缺血模型在缺血24 h后,Bcl-2和Bax表达发生改变,Bax表达增加在CA1区,Bcl-2表达增加在CA3区和齿状回.

Bcl-2 and Bax expressions in hippocampus in cerebral ischemic mouse model

BACKGROUND: The utilization of cerebral ischemia model established on C57black/6 mouse has been significantly increased in the researches. At present, it is necessary to completely and thoroughly investigate the molecular biological changes in neuronal injury and death of the model. Our study is to observe the expression levels of two genes that are closely correlated with ischemic neuron death.OBJECTIVE: To observe Bcl-2 and Bax expressions in hippocampus after ischemia on cerebral ischemic mouse model for the investigation of this animal model on proteinic molecular expression level, which would provide a laboratorial gist for future application of this animal model in cerebral ischemia researches.DESIGN: A randomized controlled perspective study based on experimental animals as subjects.SETTING: Departments of Physiology and Pathoanatomy of some university.PARTICIPANTS: The study was conducted in the Department of Physiology of Capital Medical University from November 2002 to May 2003. Twelve C57black/6 mice were selected and randomly divided into sham-operation group and ischemia group with 6 mice each.INTERVENTIONS: Cerebral ischemic model was induced by occluding both common carotid arteries for 15 minutes. Brain tissues were harvested after 24 hours. Bcl-2 and Bax expressions in hippocampus were observed after post-cerebral ischemic immunohistochemical staining.MAIN OUTCOME MEASURES: Bcl-2 and Bax expressions in hippocampus.RESULTS: The number of Bax-positive immune reaction(IR) neuron in hippocampal CA1 area was(57.3 ± 2.9) in ischemia group, which was significantly more than(17.2 ± 1.3) of sham-operation group( t = 30.91,P ＜ 0.05). The number of Bcl-2-IR-positive neuron in hippocampal CA3 and dentate gyrus was(43. 9 ± 1.1 ) in ischemia group, which was significantly more than(28; 6 ± 1.7) in sham-operation group( t = 18.51, P ＜ 0. 05) . As indicated by the results of positive staining grey scale measurements, Bax-IR positive grey scale in hippocampal CA1 area was (90.45 ± 5.23 ) in ischemia group, which was significantly lower than (168.39 ± 4.55) in sham-operation group( t =27.54, P ＜ 0. 05); Bcl-2-IR positive grey scale in CA3 area and dentate gyrus was(113.10±4. 20), which was significantly lower than( 157.25 ± 7.68) in sham-operation group( t = 12.35, P ＜ 0. 05).CONCLUSION: Bcl-2 and Bax expressions change after 24 hours of ischemia in cerebral ischemic mouse model. Bax expression increases in CA1area while Bcl-2 expression increases in CA3 and dentate gyrus.