Hyperoxia exposure impairs surfactant function and metabolism.
OBJECTIVE
To evaluate the effects of hyperoxia exposure on lung function and the endogenous surfactant system in spontaneously breathing adult rats.


METHODS
Analysis of the pulmonary surfactant system isolated from adult rats following exposure to > 90% oxygen or room air for 48 or 72 hrs.


METHODS
A basic science research laboratory in a university setting.


METHODS
Sixty pathogen-free Sprague-Dawley rats.


METHODS
Exposure to > 90% oxygen for 72 hrs.


RESULTS
Exposure to > 90% oxygen for 72 hrs resulted in significant lung dysfunction and an increase in neutrophils and total protein concentrations within the airspace compared with animals exposed to room air or 48 hrs of 90% oxygen exposure. Total alveolar surfactant and large aggregate pool sizes were increased after 72 hrs of hyperoxia compared with the other groups, and there was evidence of lipid peroxidation within these large aggregate subtractions. The biophysical function of large aggregate isolated from 72-hr hyperoxia-exposed animals was also impaired and converted into small aggregate forms faster than large aggregate from normoxia-exposed animals when assessed using in vitro surface area cycling techniques.


CONCLUSIONS
Oxidative stress on the endogenous surfactant system may represent an important mechanism contributing to the surfactant dysfunction and abnormal surfactant metabolism associated with hyperoxia-induced lung injury.
Zenri
Hiromi
H
Department of Medicine, Lawson Health Research Institute, St. Joseph's Health Centre, The University of Western Ontario, London, Ontario, Canada.
Rodriquez-Capote
Karina
K
McCaig
Lynda
L
Yao
Li-Juan
LJ
Brackenbury
Angela
A
Possmayer
Fred
F
Veldhuizen
Ruud
R
Lewis
Jim
J
D000208:Acute Disease; D000327:Adsorption; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D004195:Disease Models, Animal; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D018496:Hyperoxia / Q000150:complications*; D007958:Leukocyte Count; D015227:Lipid Peroxidation; D008170:Lung Compliance; D055370:Lung Injury; D008297:Male; D009000:Monocytes / Q000276:immunology / Q000378:metabolism; D009504:Neutrophils / Q000276:immunology / Q000378:metabolism; D018384:Oxidative Stress; D010100:Oxygen / Q000009:adverse effects*; D011663:Pulmonary Surfactants / Q000032:analysis / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012128:Respiratory Distress Syndrome / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology; D013990:Tidal Volume; D013997:Time Factors
D011663:Pulmonary Surfactants; D010100:Oxygen