Time Course of Pulmonary Capillary Permeability Changes in the Rat Exposed to 100% Oxygen

Abstract

Background: Exposure to hyperoxia causes extensive injury to lung tissue, which resembles the pathologic changes of the adult respiratory distress syndrome. To observe the relationship between the pulmonary oxygen toxicity and duration of exposure to oxygen, 100% oxygen was exposed to Wistar rats. Methods: 35 rats were partitioned into 5 groups (n=7 in each group). Gr. I breathed room air. Gr. II, III, IV and V were exposed to 99~100% oxygen for 24 hrs, 48 hrs, 60 hrs and 72 hrs. Wet lung/body weight (WW/BW), dry lung/body weight (DW/BW), wet/dry lung weight (WW/DW) and I-albumin flux ratio were measured in each group. Results: After exposure for 72 hrs in Gr. V, 3 rats were dead. WW/BW in Gr. I was 0.69±0.04 and increased to 1.10±0.28 in Gr.II (P<0.05), which was maintaind until 60 hrs. It showed marked increase in Gr. V; 2.16±0.60. DW/BW, WW/DW and I-albumin flux ratio increased after 48 hrs of hyperoxia. WW/BW and DW/BW in Gr. V and I-flux ratio in Gr. IV showed significant increase compared with Gr. I, II and III. Conclusions: The results suggest that pulmonary capillary permeability begins to change after 24 hrs of hyperoxia and that definite permeability change to albumin and fluid accumulation in the lung are demonstrable from 48 hrs-exposure to 99~100% oxygen and aggravated by duration of oxygen exposure. (Korean J Anesthesiol 1996; 30: 15~19)