Wasowicz M, Biczysko W, Marszałek A, Yokoyama S, Nakayama I
Department of Anesthesia and Intensive Care, Medical University, Poznań, Poland.
Folia Histochem Cytobiol. 1998;36(1):3-13.
As the respiratory system adapts to the extrauterine life, the extracellular matrix (ECM) plays an important structural and regulatory role during its development. Therefore the purpose of this investigation was to analyze ultrastructurally several elements of extracellular connective tissue during the process of rat lung development. Morphological observations were mainly focused on the terminal part of respiratory system. To outline different components of connective tissue network, several ultrastructural techniques were used (both histochemical and immunohistochemical). The distribution and amount of the following proteins were studied: laminin, collagen type IV, collagen fibrils (CFs), elastic fibers (EFs) and fibronectin (FN). Additionally localization of glycosaminoglycans (GAGs) was examined. The present study deals with four periods of lung development: pseudoglandular, canalicular, saccular and alveolar. In all these stages localization and amount of ECM components change rapidly. In early periods of lung development, the amount of connective tissue fibers was low, basement membranes (BMs) were incomplete, and FN was distributed nearly uniformly. Later when the process of lung alveoli formation begins, the number and thickness of both CFs and EFs rapidly increased, BMs became complete, the content and distribution of FN were irregular. In all stages of lung development GAGs were distributed in BMs and among connective tissue fibers. The results described in the present study summarize morphologically ECM changes occurring during formation of lung alveolus.
随着呼吸系统适应宫外生活，细胞外基质（ECM）在其发育过程中发挥着重要的结构和调节作用。因此，本研究的目的是在大鼠肺发育过程中，对细胞外结缔组织的几个成分进行超微结构分析。形态学观察主要集中在呼吸系统的终末部分。为了勾勒结缔组织网络的不同成分，使用了几种超微结构技术（组织化学和免疫组织化学）。研究了以下蛋白质的分布和含量：层粘连蛋白、IV型胶原、胶原纤维（CFs）、弹性纤维（EFs）和纤连蛋白（FN）。此外，还检测了糖胺聚糖（GAGs）的定位。本研究涉及肺发育的四个时期：假腺期、小管期、囊状期和肺泡期。在所有这些阶段，ECM成分的定位和含量都迅速变化。在肺发育的早期，结缔组织纤维的数量较少，基底膜（BMs）不完整，FN分布几乎均匀。后来，当肺泡形成过程开始时，CFs和EFs的数量和厚度迅速增加，BMs变得完整，FN的含量和分布不规则。在肺发育的所有阶段，GAGs都分布在BMs和结缔组织纤维之间。本研究中描述的结果总结了肺泡形成过程中发生的ECM形态学变化。
