Horwitz A L, Crystal R C
J Clin Invest. 1975 Nov;56(5):1312-8. doi: 10.1172/JCI108207.
The function of lung is fundamentally linked to the connective tissue composition of the alveolar interstitium. The composition and synthesis of one class of interstitial connective tissue components, the glycosaminoglycans (GAG), was determined in lung parenchyma of rabbits at different stages of development. Parenchymal GAG content ranged between 0.2 and 0.4% (wt/wt) of dry weight, with highest concentration in adult lung. There were significant changes in types of GAG present at different ages. Fetal lungs contained a relatively high proportion of chondroitin 4-sulfate while the GAG in lung parenchyma of older animals was predominantly dermatan sulfate, heparan sulfate, and heparin. Methods were developed for the study of rates of synthesis of GAG by incorporation of [1-14C]glucosamine into lung explants. The rate of synthesis of total GAG per cell increased with development to a maximum in lung from weanling rabbits and fell to low rates of synthesis in mature rabbits. Fetal rabbit lung parenchyma synthesized mostly hyaluronic acid and heparan sulfate, while in weanling rabbit parenchyma hyaluronic acid and chondroitin 4/6-sulfate synthesis was greatest. In mature animals, the rates of synthesis of all types of GAG were relatively low but there was a relatively greater emphasis on synthesis of dermatan sulfate and heparin. These results may have significance in changes in lung function during development and in effects on other connective tissue components.
肺的功能从根本上与肺泡间质的结缔组织组成相关。在兔子发育的不同阶段，对一类间质结缔组织成分——糖胺聚糖（GAG）的组成和合成进行了测定。实质组织中GAG的含量占干重的0.2%至0.4%（重量/重量），在成年肺中浓度最高。不同年龄段存在的GAG类型有显著变化。胎儿肺中硫酸软骨素4 - 硫酸盐的比例相对较高，而老年动物肺实质中的GAG主要是硫酸皮肤素、硫酸乙酰肝素和肝素。通过将[1 - 14C]葡糖胺掺入肺外植体来研究GAG合成速率的方法得以开发。每个细胞中总GAG的合成速率随着发育而增加，在断奶兔的肺中达到最大值，而在成熟兔中则降至低合成速率。胎儿兔肺实质主要合成透明质酸和硫酸乙酰肝素，而在断奶兔实质中，透明质酸和硫酸软骨素4/6 - 硫酸盐的合成最为显著。在成熟动物中，所有类型GAG的合成速率相对较低，但相对更侧重于硫酸皮肤素和肝素的合成。这些结果可能对发育过程中肺功能的变化以及对其他结缔组织成分的影响具有重要意义。
