Wasowicz M, Yokoyama S, Kashima K, Nakayama I
First Department of Pathology, Oita Medical University, Japan.
Acta Anat (Basel). 1996;156(4):268-82. doi: 10.1159/000147855.
The present study was designed to analyze the connective tissue compartment in the terminal region of the developing rat lung. Lungs of rat fetuses (at 17, 19 and 21 days of gestation) and of newborns (2, 4, 7, 10, 14 and 21 days after birth) were examined by several ultrastructural techniques; staining with tannic acid for elastic fibers (EFs), collagen fibers (CFs) and basement membranes (BMs); staining with ruthenium red for glycosaminoglycans; and immunoelectron microscopy for visualization of collagen type IV, laminin and fibronectin (FN). Dynamic changes in the levels and distribution of the components of the extracellular connective tissue were observed in parallel with the formation and maturation of the alveoli. The terminal regions of the respiratory tract of the rat fetus and of the lungs of early newborns contained few CFs and EFs, and the Bms in these lungs were incomplete. However, strong immunolabeling of FN was observed (in BMs, CFs and in spaces among fibroblasts). Starting from 4 to 7 days newborns had increasing numbers of Cfs and EFs and BMs became more extensive. In rat newborns, immunolabeling specific for FN was weak and irregularly distributed. Furthermore, the present results provide a summary of the changes in connective tissue that occur in the rat lung during different stages of its development, from the pseudoglandular stage, through the canalicular and saccular stages, to the alveolar stage.
本研究旨在分析发育中大鼠肺终末区域的结缔组织区室。通过几种超微结构技术对大鼠胎儿（妊娠17、19和21天）及新生儿（出生后2、4、7、10、14和21天）的肺进行检查；用单宁酸染色观察弹性纤维（EFs）、胶原纤维（CFs）和基底膜（BMs）；用钌红染色观察糖胺聚糖；并用免疫电子显微镜观察IV型胶原、层粘连蛋白和纤连蛋白（FN）。观察到细胞外结缔组织成分的水平和分布的动态变化与肺泡的形成和成熟同步。大鼠胎儿呼吸道的终末区域以及早期新生儿的肺中CFs和EFs较少，这些肺中的BMs不完整。然而，观察到FN有强烈的免疫标记（在BMs、CFs和成纤维细胞之间的间隙中）。从出生后4至7天开始，新生儿的CFs和EFs数量增加，BMs变得更广泛。在大鼠新生儿中，FN特异性免疫标记较弱且分布不规则。此外，本研究结果总结了大鼠肺在从假腺期、经小管期和囊泡期到肺泡期的不同发育阶段结缔组织发生的变化。
