Randell S H, Shimizu T, Bakewell W, Ramaekers F C, Nettesheim P
Laboratory of Pulmonary Pathobiology, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709.
Am J Respir Cell Mol Biol. 1993 May;8(5):546-55. doi: 10.1165/ajrcmb/8.5.546.
The expression of phenotypic markers was examined during fetal and neonatal differentiation of rat tracheal epithelial (RTE) cells. The rat counterpart of human keratin 18 was predominantly found in columnar cells in the adult trachea. It was detected in the primordial tracheal epithelium first seen on gestational day (GD) 12 (term = 21.5 days). Staining intensity gradually increased, and by GD 17 it was principally localized to the apical portion of the epithelium. The rat counterpart of human keratin 19 was barely detectable in the trachea on GD 13 but became abundant in almost all RTE cells on and after GD 19. Morphologically and immunocytochemically identifiable secretory and ciliated cells appeared on GD 18. Ciliated cell number slowly rose while secretory cells increased dramatically on GD 19 through postnatal day 1. The secretory granule antigens detected by monoclonal antibodies RTE 9 and 11 were rare in the adult trachea but were highly expressed in virtually all of the perinatal secretory cells. In contrast, the epitope detected by monoclonal antibody RTE 12, which was present in all adult tracheal surface secretory cells, did not appear until postnatal day 1 and slowly increased. These results demonstrate marked shifts in the biochemical composition of secretory cells during development and postnatal maturation. For the above-mentioned molecules, a similar expression pattern was observed during epithelial regeneration in tracheal grafts (Am. J. Respir. Cell Mol. Biol. 1992; 7:30-41). Pseudo-stratification of the epithelium and basal cells was first observed on GD 20. Keratin 14, which is confined to basal cells in the normal adult trachea, was not present in the nascent basal cells but appeared after postnatal day 1. In contrast to the present results, during epithelial regeneration in tracheal grafts keratin 14 appeared before markers of highly differentiated secretory or ciliated cells. Thus, the biochemical sequence of cellular differentiation during regeneration did not precisely recapitulate development.
在大鼠气管上皮（RTE）细胞的胎儿期和新生儿期分化过程中，对表型标志物的表达进行了检测。人类角蛋白18的大鼠对应物主要存在于成年气管的柱状细胞中。在妊娠第12天（足月为21.5天）首次出现的原始气管上皮中检测到了它。染色强度逐渐增加，到妊娠第17天，它主要定位于上皮的顶端部分。人类角蛋白19的大鼠对应物在妊娠第13天的气管中几乎检测不到，但在妊娠第19天及之后在几乎所有RTE细胞中变得丰富。在妊娠第18天出现了形态学和免疫细胞化学可识别的分泌细胞和纤毛细胞。纤毛细胞数量缓慢增加，而分泌细胞在妊娠第19天至出生后第1天急剧增加。单克隆抗体RTE 9和11检测到的分泌颗粒抗原在成年气管中很少见，但在几乎所有围产期分泌细胞中高度表达。相比之下，单克隆抗体RTE 12检测到的表位存在于所有成年气管表面分泌细胞中，直到出生后第1天才出现并缓慢增加。这些结果表明，在发育和出生后成熟过程中，分泌细胞的生化组成发生了显著变化。对于上述分子，在气管移植物的上皮再生过程中观察到了类似的表达模式（《美国呼吸细胞与分子生物学杂志》1992年；7：30 - 41）。上皮和基底细胞的假复层在妊娠第20天首次观察到。角蛋白14局限于正常成年气管的基底细胞中，在新生基底细胞中不存在，但在出生后第1天之后出现。与目前的结果相反，在气管移植物的上皮再生过程中，角蛋白14在高度分化的分泌或纤毛细胞标志物之前出现。因此，再生过程中细胞分化的生化序列并没有精确地重现发育过程。
