人表皮的冷冻复型电镜观察

ELECTRON MICROSCOPY ON THE EPIDERMIS OF HUMAN SKIN BY FREEZE-FRACTURE REPLICA METHOD

本文应用冷冻复型法,对5例人小腿部脾经与胃经低电阻线下的表皮,进行了电镜观察。发现棘细胞具有粗大突起和微绒毛。颗粒细胞呈梭形,细胞表面呈波浪状;其胞膜的劈裂面上膜内微粒较棘细胞者少;但膜被颗粒的外排小孔则较之为多,其大小为50~75nm,平均数为47.5/μm;胞质内除个别线粒体外,主要为呈各种走向的张力细丝束;其间散布着膜被颗粒,接近角化细胞者多位于胞膜下方,直径为60~88nm。颗粒细胞核膜的膜内微粒及按孔均很稀少。角化细胞呈扁平状,胞膜明显增厚,其劈裂面上除桥粒区外,无膜内微粒和外排小孔;深层细胞的胞质可见大量细丝,而浅层者胞质呈均质状。桥粒在深层细胞多,至角化层渐减少,且呈退化状态。在颗粒层细胞间隙内,可见由膜被颗粒外排物质先附于细胞外表面,继而出现板层状膜及原纤维状结构,后者直径为70~100nm,具有间距为60~70nm的横纹。

Electron microscopy on the epidermis of the skin on the low impedence lines of 5 human legs were studied by freeze-fracture replica method.It was revealed that prickle cells possess thick processes and microvilli;while granular cells are short spindle in shape,its surface is undulating in appearance,on the fractured face of its cell membrane there are less intramembraneous particles(IMP)and more exocytotic pores of the membrane-coating granules(MCG)than those of the prickle cells.The diameter of the exocytotic pores is 50-75 nm,and its mean number is 47.5/μm~2.In the cytoplasm of granular cell,except individual mitochondrion,there are many tonofilament bundles running in various directions and between them a number of MCGs are scattered.The MCGs in the superfical granular cells occurred under the cell membrane are 60-88 nm in diameter.On the nuclear membrane of granular cell both IMP and nuclear pores are scarce.The horny cells are scale in shape,its cell membrane thickens enormously,on its fractured face,except the desmosome area there is no IMP and exocytotic pore,in the cytoplasm of the deep horny cell there are a lot of microfilaments,while in the superfical one the cytoplasm is homogeneous.The desmosomes are many more in the deep layer cells,than the horny cells.Desmosomes in the superfical horny cells are degenerative in appearance.In the intercellular spaces of granular layer homogeneous substance expelled out from MCGs somewhat like paint attaching on the outer surface of the cell membrane at first,and then smooth surfaced laminated structure and filaments which run in spiral fashion in bundles to form fibrils were revealed.The diameter of the fibrils is 70-100 nm and the periodicity on them is 60-70 nm.This kind of fibrils has never been reported in literatures.