大鼠低氧肺损伤的超微结构及肺泡液体清除功能的变化

Structural and Alveolar Fluid Clearance Changes in Hypoxic Rat Lungs

目的研究肺损伤大鼠肺泡液体清除率（alveolar flui dclearance，AFC）及肺脏超微结构的变化规律，并探讨二者的内在联系。方法雄性Wistar大鼠120只，体重300～380g，随机分成12组，低氧大鼠暴露于10％的氧浓度，分别于24、48和72h测定基础AFC、特布他林作用后AFC、总肺水量（totallung water，TLW），并取病理切片观察肺脏超微结构的变化。结果大鼠暴露于10％的氧浓度24h后AFC（18．7±3．19％）与正常大鼠AFC（18．9±2．26％）比较没有明显变化，内皮细胞出现损伤改变，而上皮细胞并没有明显的结构变化；48h时AFC（13．6±2．60％）明显降低，但肺泡上皮细胞的结构和上皮细胞紧密连接并无明显损伤；72h AFC（9．93±1．95％）进一步降低，且经特布他林作用后AFC（12．7±2．64％）仍低于对照组基础AFC，肺泡上皮细胞的结构破坏。结论当轻、中度损伤时，虽AFC降低，但肺泡上皮屏障的结构可以没有明显改变，对药物有较好的反应性。

Objective To study the ultrastmctural and alveolar fluid clearance （AFC） changes in hypoxic rat lungs, and to investigate the relationship between them. Methods One hundred and twenty male Wistar rats weighing 300 - 380 g were randomly divided into twelve groups. The hypoxic rats were generated by exposure to 10% oxygen. Basal AFC and total lung water （TLW） stimulated by terbutaline were measured at 24 h, 48 h and 72 h, respectively. The specimens were examined by electron microscopy. Results After the rats were exposed to 10 % oxygen concentration for 24 h, the level of AFC （18.7 ± 3.19 % ） showed no marked difference compared with that of normal rats （18.9± 2.26% ）. The capillary endothelial cells had some injury changes while the alveolar epithelial cell showed no remarkable change. At 48 h, AFC （ 13.6± 2.60% ） decreased markedly while the alveolar epithehal cells had no obvious structural change. At 72 h, the level of AFC （9.93 ±1.95% ） decreased further, and the AFC stimulated by terbutaline showed marked difference with that of normal rats. The alveolar epithelial cells presented marked changes. Conclusion In the setting of mild and moderate lung injury, although AFC is deceased, the structure of alveolar epithelial barrier may not necessarily be markedly changed, and the response to drug effects upon AFC can still be well maintained.