Kong Xiang-Yong, An Jing, Feng Zhi-Chun
Department of Pediatrics, Zhujiang Hospital, First Military Medical University, Guangzhou 510282, China.
Di Yi Jun Yi Da Xue Xue Bao. 2004 Jan;24(1):72-4, 78.
To observe the development of the alveoli and the differentiation of the epithelium in the fetal lung of Chinese.
Chinese human lung tissues were obtained from 20 fetuses of 10 to 34 weeks old, and the ultrastructural changes of the alveolar epithelial cells were observed using both optical and transmission electron microscope.
At the first 10 to 16 weeks of development, the lung showed a tubular structure, the epithelial cells were columnar and poorly differentiated. At weeks 17 to 24, the bronchioles increased and the epithelial cells were differentiated to approach maturity. A few lamellar bodies were observed in the cuboidal lining cells with the majority being type II alveolar cells at 25 weeks, when the primitive alveolar was formed. In this stage many primitive epithelial cells could be seen, which appeared primordial in form before evolving into type II and type I cells and perhaps served as epithelial stem cells or progenitor cells. From about 26 weeks, type I cells were observed but most of the epithelial cells were type II cells. Type I cells began to increase in the alveolar epithelium until 32 weeks.
The alveolar type II cells and type I cells are probably both derived from the same precursor cells or stem cells, and no evidence has shown that type II cells may differentiate into type I cells during the development of the fetal lung.
观察中国人胎儿肺中肺泡的发育及上皮细胞的分化情况。
获取20例10至34周龄中国人胎儿的肺组织，用光镜和透射电镜观察肺泡上皮细胞的超微结构变化。
在发育的最初10至16周，肺呈管状结构，上皮细胞为柱状且分化程度低。在17至24周时，细支气管增多，上皮细胞分化接近成熟。在25周形成原始肺泡时，立方状衬里细胞中可见少量板层小体，多数为II型肺泡细胞。在此阶段可见许多原始上皮细胞，它们在演变为II型和I型细胞之前形态原始，可能是上皮干细胞或祖细胞。从约26周开始观察到I型细胞，但大多数上皮细胞为II型细胞。I型细胞在肺泡上皮中开始增多直至32周。
II型肺泡细胞和I型细胞可能都来源于同一前体细胞或干细胞，且尚无证据表明在胎儿肺发育过程中II型细胞可分化为I型细胞。
