血管性痴呆大鼠海马CA1区神经元超微结构的长时程变化

目的观察血管性痴呆（VD）大鼠长时期海马组织学和CA1区神经元超微结构的动态变化规律。方法60只大鼠随机分为假手术组、模型7d组、模型15d组、模型1m组、模型2m组和模型4m组,每组10只。光镜和电镜下观察各组大鼠海马组织学和CA1区超微结构的改变。结果①光镜下假手术组大鼠海马CA1区未见明显病理变化,但模型组大鼠海马CA1区锥体细胞数量减少,细胞变性坏死,细胞明显水肿,排列紊乱;细胞核体积变小,深染,呈核固缩表现,顶树突缩短,排列紊乱。另外,模型1m组可见胶质细胞明显增生,模型2m组和4m组胶质细胞明显增生形成结节,呈现海马硬化表征。②电镜下可见神经细胞及神经末梢水肿、胞浆内有色素沉积、细胞膜断裂、核染色质边集、细胞核溶解、核周隙增宽,线粒体肿胀,嵴紊乱断裂,破坏严重。随造模时间的延长,病理改变逐渐加重。结论血管性痴呆发生和发展中海马CA1区锥体细胞严重脱失,神经元变性坏死,超微结构受损,并逐渐加重。

Long-Term Changes of Neuronal Ultrastructures of Hippocampal CA1 Area in Vascular Dementia Rats

Objective To observe the long-term changes of histological structure and neuronal ultrastructure of hippocampal CA1 area in vascular dementia（VD） rats.Methods VD rat models were established.Sixty rats were randomly divided into the sham-operated group（SO）,7-day VD model group（7dM）,15-day VD model group（15dM）,1-month VD model group（1mM）,2-month VD model group（2mM） and 4-month VD model group（4mM）.The histological structure and neuronal ultrastructure of hippocampal CA1 area were observed under light and electron microscope.Results ①No significant pathological changes were revealed under light microscope in SO group.Compared with the SO group,the number of the pyramidal neurons of hippocampal CA1 area was obviously reduced,the dropsically denatured and necrotic pyramidal neurons of hippocampal CA1 area were revealed and their arrangement disorganized,their apical dendrites distinctly shortened,their nuclei shrinked,deep stained and condensed in hippocampal slices of each model group under light microscope.Neuroglia hyperplasia of CA1 area was observed in 1mM,2mM and 4mM groups and neuroglia hyperplasia nude formed in 2mM and 4mM groups which showed a sign of hippocampal sclerosis.②It revealed that edema in neurons and their ending,sedimentary pigment in cell plasma,cell membrane rupture,nucleus chromatin margination,nucleolus dissolution,locally widened perinuclear cisterna,mitochondria swelling,mitochondrial crista chaos and rupturing and a lot of vacuolated mitochondria in electron microscopic slices of hippocampal CA1 area in the model groups.Above pathological changes were progressive along with the time prolongation after cerebral ischemia/reperfusion.No obviously pathological changes were observed in SO group under electron microscope.Conclusion The number of the pyramidal neurons of hippocampal CA1 area was obviously decreased and the denatured and necrotic pyramidal neurons and severely injured ultrastructures of neurons in CA1 area were revealed and progressively aggravated d