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目的 观察小鼠胚胎及生后肺泡发育及肺泡上皮分化。方法 小鼠胚胎 14天至生后 14天肺组织 ,隔天取材 ,HE染色光镜观察及透射电镜观察。结果 胚胎 14～ 18天 ,小鼠肺的发育以支气管树分支和管壁结构的逐渐完善为主 ,终蕾上皮为柱状或立方状的未分化细胞。胚胎 19天 ,支气管远端形成许多内壁光滑的原始肺泡 ,其上皮分化出Ⅱ型肺泡细胞。生后 1～ 4天 ,肺泡上皮出现少量扁平的Ⅰ型肺泡细胞 ,但仍以Ⅱ型肺泡细胞为主。生后 5～ 14天 ,成熟肺泡形成 ,肺泡上皮以Ⅰ型肺泡细胞为主。结论 出生时 ,小鼠的肺发育只完成了其大体形态的发生 ,肺泡上皮以Ⅱ型肺泡细胞为主。成熟肺泡的形成、数量的增加及Ⅰ型肺泡细胞的大量出现持续到出生后。
Objective To observe the alveolar development and alveolar epithelial differentiation in embryos and postnatal mice. Methods The lung tissues from 14 days after embryo to 14 days after birth were harvested and stained with HE stain and transmission electron microscopy. Results The embryo developed from 14 to 18 days in embryo. The development of lung in mice mainly consisted of gradual improvement of bronchial tree branches and wall structure. The terminal bud epithelium was columnar or cubic undifferentiated cells. On the 19th day of embryo, many primitive smooth alveoli with smooth inner wall were formed on the distal end of bronchus, and the type II alveolar cells differentiated from the epithelium. 1 to 4 days after birth, a small amount of flat alveolar epithelial alveolar cells, but still type Ⅱ alveolar cells. 5 to 14 days after birth, the formation of mature alveoli, alveolar epithelial type Ⅰ alveolar cells. Conclusion At birth, lung development in mice only completed its general morphology. Type II alveolar cells dominated the alveolar epithelium. The formation of mature alveoli, an increase in the number, and a large number of type I alveolar cells continue until after birth.