急性重复缺氧小鼠海马CA1区的超微结构观察

Ultrastructure of CA1 area of hippocampus in mice with acute repetitive hypoxia

目的 从亚细胞水平了解小鼠在不同次数急性重复缺氧时海马CA1区神经细胞、星形胶质细胞和毛细血管的变化规律。方法 将昆明小鼠随机分成 1次、2次及 4次急性重复缺氧实验组及对照组 ,存活 7d后麻醉 ,立即灌杀 ,取海马CA1区组织 ,常规电镜制片 ,透射电镜下观察。结果 与对照组相比 ,不同缺氧次数实验组均呈不同程度变化 ,主要表现为神经元胞核染色质有大、小不等团块凝集的凋亡倾向。星形胶质细胞出现微管、微丝明显减少甚至消失 ,严重者胞浆结构除线粒体外全无 ;胞核缩小 ,核染色质在核膜周围有明显团块凝集 ,呈“半月形” ,严重者胞核结构全无 ;凋亡、坏死 ;突起的出现微管、微丝模糊或消失 ,线粒体结构不清的退行性变。D 7H 4实验组上述表现明显。毛细血管无病理变化。结论 急性重复缺氧有累加损伤作用 。

Objective To observe the ultrastructural changes in neurons,astrocytes and blood capillaries of CA1 area in mouse hippocampus after different times of acute repetitive hypoxia and survival for 7 days.Methods Kunming mice were randomly classified into groups with once,twice and four times of acute hypoxia and control group.The tissues in CA1 area of hippocampus were observed under electron microscope.Results Compared with control group,ultrastructural changes in different extent appeared in groups with once,twice and four times of acute hypoxia The neurons tended to develop apoptosis,the chromatins in nucleus aggregated into different size of maAss.The astrocytes also manifested apoptosis or necrosis,the microfilaments and microtubules of astrocytes decreased in number obviously ,even disappeared, and in seriouscases,the whole structure of cytoplasm disappeared except the mitochondria;the nucleus reduced in size ,the chromatins in nucleus aggregated into different size of lumps around nuclear membrane and appeared in the shape 'half moon',and in seriouscases,the whole structure of nucleus disappeared.The dendrites of astrocytes degenerated,the structure of microfilaments and microtubules was obscure,even disappeared,and the structure of mitochondria was indistinct.The above changes were prominent in the group with four times of acute repetitive hypoxia.There was no change in blood capillaries.Conclusions There is accumulated damage in the neurons and satrocytes of CA1 area in mouse hippocampus after acute repetitive hypoxia and the astrocytes of CA1 area are the cells vulnerable to hypoxia.