Schuster G S, Singh B B, Erbland J F, Steflik D E, Ringler M B
Scan Electron Microsc. 1981(Pt 3):383-9.
Recently our laboratories have successfully attained preferential epithelial outgrowths from hamster cheek pouch explants. This has allowed us to systematically analyze oral epithelial cell differentiation as weel las examine the modulatory effects of various physiologic and pharmacologic agents in this epithelial cell system. The objective of the current investigation was to study the effects of various doses of retinoic acid (RA) on the epithelial outgrowths of hamster cheek pouch. Light microscopic observations employing colcemid treatment indicated that 10 IU/ml RA enhanced mitotic activity of the epithelium up to 25%. Scanning electron microscopic observations of control cultures showed flat, polyhedral epithelial cells containing thin long microvilli connecting the adjacent cells. In contrast, cultures treated with 10 IU/ml RA showed round or spherical cells exhibiting short of medium sized thicker microvilli. These were covered with a fuzzy appearing layer probably representing glycocalyx. Many bleb-like formation were also observed. Transmission electron microscopic examination of the control cultures showed the presence of tonofilaments and desmosomes, characteristic components of the keratinizing epithelia. In contrast, the RA treated cultures included cells which apparently were either devoid of tonofilaments or contained few fine filaments and small intercellular functions. In addition many vacuoles as well as variable numbers of electron-dense and electron-lucent granules were observed. Thus, it appears that RA inhibited keratinization and altered the differentiation pattern of keratinization and altered the differentiation pattern of keratinizing epithelium.
最近，我们的实验室已成功地从仓鼠颊囊外植体中获得了优先的上皮细胞生长。这使我们能够系统地分析口腔上皮细胞的分化情况，并研究各种生理和药理试剂在这个上皮细胞系统中的调节作用。当前研究的目的是探讨不同剂量的视黄酸（RA）对仓鼠颊囊上皮细胞生长的影响。采用秋水仙酰胺处理的光学显微镜观察表明，10 IU/ml的RA可使上皮细胞的有丝分裂活性提高达25%。对照培养物的扫描电子显微镜观察显示，扁平的多面体上皮细胞含有连接相邻细胞的细长微绒毛。相比之下，用10 IU/ml RA处理的培养物显示出圆形或球形细胞，其具有短至中等大小的较粗微绒毛。这些细胞覆盖着一层模糊的物质，可能代表糖萼。还观察到许多泡状结构。对照培养物的透射电子显微镜检查显示存在张力丝和桥粒，这是角化上皮的特征性成分。相比之下，经RA处理的培养物中的细胞显然要么没有张力丝，要么含有很少的细丝和小的细胞间连接。此外，还观察到许多液泡以及数量不等的电子致密和电子透亮颗粒。因此，似乎RA抑制了角质化，并改变了角质化的分化模式以及角质化上皮的分化模式。
