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Hyperoxic lung injury: biochemical, cellular, and morphologic characterization in the mouse
The Journal of Laboratory and Clinical Medicine
|September 1, 1985
Summary
High oxygen exposure causes lung damage in mice, marked by changes in lactate dehydrogenase (LDH) and angiotensin-converting enzyme (ACE) levels. Initial injury occurs before polymorphonuclear leukocytes (PMNs) infiltration.
Area of Science:
- Pulmonary Medicine
- Toxicology
- Cell Biology
Background:
- The precise mechanisms of oxygen-induced lung injury remain debated.
- Understanding these mechanisms is crucial for developing effective treatments.
Purpose of the Study:
- To characterize the biochemical, cellular, and morphologic responses of mice to 100% oxygen exposure.
- To establish a well-defined model for studying hyperoxic lung injury mechanisms and evaluating treatments.
Main Methods:
- Mice were exposed to 100% oxygen for up to 5 days.
- Biochemical markers (LDH, ACE), bronchoalveolar lavage (BAL) cell counts and protein, and electron microscopy were analyzed.
- Changes were monitored daily throughout the exposure period.
Main Results:
- Plasma LDH activity and specific isoenzymes increased, while lung isoenzyme 1 decreased, serving as sensitive markers.
- Early exposure (day 2) showed type 1 cell and endothelial cell damage, preceding significant polymorphonuclear leukocyte (PMN) infiltration.
- BAL protein and cell counts, along with BAL ACE activity, increased significantly by day 3, with mortality reaching over 65% by day 5.
Conclusions:
- Elevated plasma LDH and altered isoenzyme patterns are sensitive indicators of hyperoxic lung damage.
- The initial lung injury induced by oxygen is independent of PMNs.
- Severe damage to alveolar epithelial and endothelial cells occurs concurrently and early in oxygen exposure.