Webster E H, Hilfer S R, Searls R L, Kornilow J
Department of Biology, Temple University, Philadelphia, Pennsylvania 19122.
Am J Physiol. 1993 Sep;265(3 Pt 1):L250-9. doi: 10.1152/ajplung.1993.265.3.L250.
The mesodermal capsule of the fetal lung plays a role in differentiation of the respiratory region. It has been proposed for other epithelial organs that the mesodermal capsule influences development by modifying the basal lamina or the extended extracellular matrix. The effect could be on deposition or turnover of collagens, proteoglycans, and/or glycoproteins. This study tests the role of glycoproteins in differentiation of respiratory endings by inhibiting their synthesis with the antibiotic tunicamycin (TM). Lungs at 16 and 18 days gestation and 3 days after birth were cultured with TM and examined for morphological and biochemical differences from normal controls. With TM, alveolar regions did not expand properly and formed fewer type I pneumocytes, although type II pneumocytes were unaffected. The epithelium of untreated respiratory regions showed greater incorporation of radioactive mannose than the airways region or mesenchyme. This incorporation was diminished in TM, but the pattern persisted. Comparison with the results obtained with beta-xyloside suggested that differentiation of type I and type II pneumocytes is under separate control.
胎儿肺的中胚层被膜在呼吸区域的分化中起作用。对于其他上皮器官，有人提出中胚层被膜通过修饰基膜或扩展的细胞外基质来影响发育。这种影响可能涉及胶原蛋白、蛋白聚糖和/或糖蛋白的沉积或周转。本研究通过用抗生素衣霉素（TM）抑制糖蛋白的合成来测试糖蛋白在呼吸末梢分化中的作用。对妊娠16天和18天以及出生后3天的肺进行TM培养，并检查其与正常对照在形态和生化方面的差异。使用TM时，肺泡区域不能正常扩张，I型肺细胞形成减少，而II型肺细胞未受影响。未处理的呼吸区域的上皮比气道区域或间充质显示出更高的放射性甘露糖掺入。TM处理后这种掺入减少，但模式仍然存在。与用β-木糖苷获得的结果比较表明，I型和II型肺细胞的分化受不同的控制。
