Ultrastructural alteration of pulmonary tissue under conditions of high oxygen concentration.

OBJECTIVE

To determine the structure of pulmonary tissue under conditions of high oxygen concentration.

METHODS

Ten-week-old C57BL male mice and control mice were exposed to 100% oxygen and to room air for 72 hours, respectively. To follow the progression of lesions, the mice were sacrificed at 6, 12, 24, 48, and 72 hours after 100% oxygen administration. Lung specimens obtained from these mice underwent morphologic analysis and immunofluorescence studies. We used scanning and transmission electron microscopy to determine the ultrastructure of the pulmonary capillaries, including the endothelial glycocalyx. To visualize the endothelial glycocalyx, we performed lanthanum nitrate staining.

RESULTS

The survival rate of the 100% oxygen administration group was 5% (2/40) and that of the control group was 100%. Perivascular cavity enlargement was detected 12 hours after 100% oxygen administration and expanded over time. Ultrastructural analysis using electron microscopy revealed collapsed alveoli and pulmonary capillary wall and alveolar wall thickening in the 100% oxygen group. The pulmonary capillary endothelial glycocalyx was injured in the 100% oxygen group. The perivascular cavity decreased in mice that were returned to room air after 48 hours of 100% oxygen administration.

CONCLUSION

High-concentration oxygen causes perivascular cavity enlargement; this is thought to be a special characteristic of high oxygen damage. In addition, high-concentration oxygen may be involved in pulmonary endothelial glycocalyx injury.