title: Alveolar epithelial changes in rabbits after a 21-day exposure to 60% O2.
abstract: This study characterizes the biochemical and physiological effects of prolonged exposure of rabbits to sublethal (60%) O2 concentrations. After 3 wk in 60% O2, rabbits had arterial PO2 values of 69 +/- 2 vs. 79 +/- 3 Torr for control animals (means +/- SE; P less than 0.05) and a small but significant rise in pulmonary wet weight-to-dry weight ratios (5.6 +/- 0.3 vs. 4.1 +/- 0.3; P less than 0.05). Alveolar permeability to solute, lung compliance, total lung capacity, and alveolar protein levels were unchanged from control, but the amount of lavagable alveolar phospholipid was 90% higher in the O2-exposed rabbits. The lipid biosynthetic ability of isolated alveolar type II pneumocytes, measured by radiolabeled precursor [3H]choline incorporation, indicated that type II cells isolated from hyperoxic animals synthesized phosphatidylcholine at a rate 110% higher than those from control animals. Laser flow cytometric analyses of isolated type II cells showed a significant increase in type II cell diameter, based on time-of-flight measurements, and an average 60% increase in lipid content per cell, based on phosphine-3R fluorescence intensity. These findings indicate that exposure to 60% O2 for 21 days results in a decrease in arterial PO2 and induces several important biochemical and morphological changes in alveolar type II pneumocytes.
mesh_terms: D000818:Animals; D001784:Blood Gas Analysis; D004848:Epithelium / Q000187:drug effects; D005434:Flow Cytometry; D006400:Hematocrit; D006863:Hydrogen-Ion Concentration; D007834:Lasers; D008297:Male; D010100:Oxygen / Q000633:toxicity*; D010539:Permeability; D011650:Pulmonary Alveoli / Q000166:cytology*; D011817:Rabbits; D013997:Time Factors
chemical_list: D010100:Oxygen