胎儿甲襞血管的电镜观察

目的 :观察胎儿甲襞血管的发生和形成 ,为认识生理性血管形成和病理性血管形成提供依据。方法 :电子显微镜观察正常胎儿 (5～ 9月胎龄 )甲襞皮肤血管的超微结构。结果 :5～ 9月龄胎儿甲襞皮肤血管的超微结构呈现出由新生幼稚到初步成熟的过程。每一例胎儿的标本都有不同发育阶段的血管。再由毛细血管分化为细静脉、细动脉。 5～ 9月龄胎儿甲襞皮肤中最原始的血管前体 ,只是在胶原纤维及成纤维细胞之间出现隙、溪、池 ,进而形成一个没有内皮细胞围绕的腔隙 ,称之为“毛细血管前腔隙”。进而形成不成熟的毛细血管。不成熟的毛细血管在超微结构上仍残有毛细血管前腔隙的一些结构。结论 :胎儿微血管的超微结构有以下特点 :(1)管壁细胞结构很不发达 ;(2 )内皮细胞发育不同步 ,最初微丝占据很大空间 ,线粒体和粗面内质网出现较早 ;(3 )平滑肌纤维出现很晚 ,发育不良。在细动脉、小动脉、小静脉的管壁 ,很少出现典型的平滑肌细胞的结构。

Electron Microscopic Observation of Microvessels at Nailfold Skin in Fetus/TianNiu,Liu Fengying,Zhu Guangming,et al

Objective: To observe the microvascular ultrastructure of nailfold skin of fetus in order to understand further the physiological and pathological neoangiogenesis in human being.Method: The specimens of nailfold skin were taken from eight aborted fetus of 5～9 months old.The blocks of skin tissue were fixed in glutaldehyde,followed by routine post-fixation,dehydration,embedding and staining,then observed under electron microscope.Results: The ultrastructure of the skin vessels on human fetus of 5～9th mounth old showed several stages of the developing process of vessels,from primary precanalof capillaries in the mesenchymal tissue to the newly formed vessels.The homogeneous structure of low electron density with the shape of breack,shelf and river like were revealed between collagen fibers and mesenchymal cells,which formed large lumen without endothelial cells and were called precapillary lumen.Newly formed capillaries were developed from them.Conclusion: Some characteristic features in ultrastructure of microvessels in fetus skin could be summarized here:(1)The development of ultrastructutre of microvesseles wall in fetus was immature in examined fetus;(2)The development of endothelial cells were asymchrometric,microfibrillious elements occupied the most part of plasma area,mitrochondria and rough-surfaced endoplasmic reticulum were organelles,which appeared earlier;(3)The development of smooth muscle cells or layer of smooth muscle cells was insufficent or immature,and the typical structure of smooth muscle layer was absent in wall of arterioles,small arteries and small veins.