Unattenuated structural and biochemical alterations in the rat lung during functional adaptation to ozone

Journal Article · Tue Aug 01 00:00:00 EDT 1989 · American Review of Respiratory Disease; (USA)

DOI:https://doi.org/10.1164/ajrccm/140.2.493· OSTI ID:5668313

Tepper, J S; Costa, D L; Lehmann, J R; Weber, M F; Hatch, G E ^[1]

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1. NSI Technology Services Corporation, Research Triangle Park, NC (USA)

Acute ozone (O{sub 3}) exposure in humans produces changes in pulmonary function that attenuate with repeated exposure. This phenomenon, termed adaptation, has been produced in unanesthetized rats. Rats exposed to O3 (0, 0.35, 0.5, or 1.0 ppm) for 2.25 h for 5 consecutive days showed an increased frequency of breathing and a decreased tidal volume on Days 1 and 2 of exposure at all O{sub 3} concentrations. However, by Day 5 these breathing responses to O{sub 3} were diminished in rats exposed to 0.35 and 0.5 ppm, but not in rats exposed to 1.0 ppm. In addition, a flow limitation in smaller airways was observed after the second day of exposure to 0.5 ppm O{sub 3} that initially attenuated and then disappeared by the fifth day of exposure. In contrast to these findings, a light microscopic examination of fixed lung tissue sections from rats exposed to 0.5 ppm indicated a 5-day progressive pattern of epithelial damage and inflammation in the terminal bronchiolar region. A sustained 37% increase in lavageable protein was also observed over the course of the 5-day exposure regimen to 0.5 ppm. Lung glutathione increased initially, but it was within the control range on Days 4 and 5. Lung ascorbate was significantly elevated above control levels on Days 3 and 5. These data suggest that attenuation of the pulmonary function response to O{sub 3} occurs in laboratory rats with repeated exposure while biochemical and morphologic aspects of the tissue response continue to progress.

• OSTI ID: 5668313
• Journal Information: American Review of Respiratory Disease; (USA), Vol. 140:2; ISSN 0003-0805
• Country of Publication: United States
• Language: English

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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
LUNGS
PATHOLOGICAL CHANGES
OZONE
TOXICITY
ASCORBIC ACID
BIOLOGICAL ADAPTATION
GLUTATHIONE
RATS
RESPIRATION
ANIMALS
BODY
DRUGS
MAMMALS
ORGANIC COMPOUNDS
ORGANS
PEPTIDES
POLYPEPTIDES
PROTEINS
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RESPIRATORY SYSTEM
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