Crapo J D, Peters-Golden M, Marsh-Salin J, Shelburne J S
Lab Invest. 1978 Dec;39(6):640-53.
Animals exposed to 85 per cent O2 for 5 or more days acquire the ability to survive for prolonged periods in 100 per cent O2. The basis of this acquired "tolerance" is poorly understood, but it has been proposed to be related to biochemical changes occurring in the lung cells. In order to quantify the structural changes that occur in the lungs of oxygen-adapted rats, rats were exposed to 85 per cent O2 for 7 days and then studied using morphometric techniques. The oxygen-adapted rats had a normal number of alveolar type I epithelial cells and a moderate increase in the number of alveolar type II cells. The alveolar type I epithelium was intact over the entire alveolar surface and appeared to have a normal ultrastructure, whereas alveolar type II cells demonstrated occasional changes in mitochondrial structure. In the interstitial compartment, there was a large increase in the number of interstitial cells and a significant increase in the noncellular components of the interstitium. The major area of pulmonary damage occurred in the vascular compartment, where entire segments of the capillary bed were lost and the total number of endothelial cells decreased by 45 per cent. A significant change in pulmonary vascular hemodynamics was suggested by a 49 per cent decrease in total capillary lumen volume and a decrease in the hematocrit of blood in the pulmonary capillary lumen to 57 per cent of the value found in aortic blood.
暴露于85%氧气环境中5天或更长时间的动物，获得了在100%氧气环境中长时间存活的能力。这种获得性“耐受性”的基础尚不清楚，但有人提出它与肺细胞中发生的生化变化有关。为了量化适应氧气的大鼠肺部发生的结构变化，将大鼠暴露于85%氧气环境中7天，然后使用形态计量学技术进行研究。适应氧气的大鼠肺泡I型上皮细胞数量正常，肺泡II型细胞数量适度增加。肺泡I型上皮在整个肺泡表面完整，超微结构似乎正常，而肺泡II型细胞偶尔有线粒体结构变化。在间质区，间质细胞数量大幅增加，间质的非细胞成分显著增加。肺部损伤的主要区域发生在血管区，那里整个毛细血管床节段缺失，内皮细胞总数减少了45%。总毛细血管腔体积减少49%，肺毛细血管腔内血液的血细胞比容降至主动脉血中值的57%，提示肺血管血流动力学发生了显著变化。
