血管性痴呆小鼠海马神经元超微病理特征研究

Ultrastructural pathologic features of neuron of hippocampus in the mice with vascular dementia

目的:探讨血管性痴呆(VD)小鼠海马神经元超微病理特征及其变化的意义。方法:采用双侧颈总动脉线结、反复缺血 再灌注法,制作小鼠VD动物模型。取两组小鼠海马组织制成超薄切片,透射电镜观察。结果:(1)假手术组:海马神经元和神经毡结构均正常。(2)VD模型组:海马神经元核肿胀、有局部凹陷现象;核周体细胞器明显减少,多聚核糖体稀散;仅残留受到破坏的高尔基体和粗面内质网、线粒体变性。髓鞘层裂;轴突中神经微管结构模糊。神经毡中可见树突和轴突不同程度水肿,尤其是树突呈现极度扩张形成不规则的"气球",其中含有许多大小不等的薄膜空泡。突触数量显著减少,可见穿孔和异形的突触;有的突触小泡破裂,呈片状均质化。结论:海马神经元的超微结构病变导致神经元功能异常、突触可塑性降低,可能在VD的病因中起重要作用。

Objective: To explore ultrastructural pathologic features of neuron of hippocampus in the mice with vascular dementia(VD)and its significance.Method: The mice were subjected for ischemia-perfusion repeatedly on bilateral common carotid arteries by knots to establish the VD models.The ultra-thin specimens of hippocampus from VD models and a sham-operated control group were observed under transmission electron microscope.Results:(1)In the sham-operated group,the neuron and neuropil of hippocampus showed ultrastractual detail of normal range.(2)In the hippocampus of VD model,the neuronal nuclei were swollen and appeared with indentation.The almost vacant perikaryon contained less organelles but rare dispersive polyribosomes.Remaining Golgi apparatus and rough endoplasmic reticulum(RER)were destructed and mitochondria degenerated.The myelin-splitting and axons with obscure neurotubule existed frequently.The axons and even the dendrites were dilated extremely to form irregular 'balloon' which contained different vacuoles in size and distorted the structure of neuropil.In neuropil,the number of synapse was reduced,perforated or dysmorphic synapses were observed,and synapse vesicles were destroyed to be homogenized.Conclusion: The ultrastructural changes of neuron of hippocampus result in dysfunction of neuron and the decrease of synapse plasticity and might take part in the important roles in the pathogenesis of VD.