Functional and morphologic changes caused by acute ozone exposure in the isolated and perfused rat lung.
Ozone has been shown to increase airway resistance and/or airway reactivity in vivo in animals and humans. Because of the complexities inherent in studying this phenomenon in whole animals, we developed a model of ozone-induced effects on airway physiology using the isolated perfused rat lung. Rat lungs were suspended in an airtight chamber and perfused via the pulmonary circulation with a modified Krebs-Henseleit buffer containing 4.5% bovine albumin. Ventilation of the lungs was achieved by generating a fluctuating negative pressure within the chamber (-2 to -7 cm H2O) at a rate of 60 breaths/min. The lungs were ventilated with humidified 95% air and 5% CO2 alone (control condition) or mixed with ozone at 1.0 or 2.0 ppm. Transpulmonary pressure, flow rate, and tidal volume were recorded at 0, 1, 2, and 3 hours, and pulmonary resistance (RL) and dynamic compliance (Cdyn) were calculated. There was no significant difference in lung weight/total body weight ratios between the three groups at the end of the 3-h period. RL increased and Cdyn decreased in a time- and dose-dependent manner with ozone exposure. The percent increase above baseline in RL +/- SEM at 3 h was 9.4 +/- 4.1% for control lungs, 21.0 +/- 3.2% for 1.0 ppm ozone-exposed lungs, and 63.6 +/- 13.5% for 2.0 ppm ozone-exposed lungs. The percent decrease below baseline in Cdyn +/- SEM at 3 h was 27.4 +/- 2.1% for control lungs, 37.1 +/- 2.7% for 1.0 ppm ozone-exposed lungs, and 55.2 +/- 7.3% for 2.0 ppm ozone-exposed lungs.(ABSTRACT TRUNCATED AT 250 WORDS)
Pino
M V
MV
California Primate Research Center, University of California, Davis 95616.
McDonald
R J
RJ
Berry
J D
JD
Joad
J P
JP
Tarkington
B K
BK
Hyde
D M
DM
D000403:Airway Resistance / Q000187:drug effects; D000818:Animals; D008168:Lung / Q000187:drug effects* / Q000502:physiology; D008170:Lung Compliance / Q000187:drug effects; D008297:Male; D008854:Microscopy, Electron; D010126:Ozone / Q000009:adverse effects*; D010477:Perfusion; D051381:Rats; D011919:Rats, Inbred Strains
D010126:Ozone