Ozone toxicity in the rat. iii. effect of changes in ambient
temperature on pulmonary parameters.
Wiester, Mildred J., William P. Watkinson, Daniel L. Costa, Kay M.
Crissman, Judy H. Richards, Darrell W. Winsett, and Jerry W.
Highfill.
Pulmonary Toxicology Branch, Experimental Toxicology Division,
National Health and Environmental Effects Research Laboratory, U.S.
Environmental Protection Agency, Research Triangle Park, North
Carolina 27711
APStracts 3:0277A, 1996.
Pulmonary toxicity of ozone (O3) was examined in adult male Fischer
344 rats exposed to 0.5 ppm ozone for either 6 or 23 h/day over 5
days while maintained at an ambient temperature (Ta) of either 10,
22, or 34 degrees C. Toxicity was evaluated using changes in lung
volumes and the concentrations of constituents of bronchoalveolar
lavage fluid that signal lung injury and/or inflammation. Results
indicated that toxicity increased as Ta decreased. Exposures
conducted at 10 degrees C were associated with the greatest decreases
in body weight and total lung capacity and the greatest increases in
lavageable protein, lysozyme, alkaline phosphatase activity, and
percent neutrophils. Ozone effects not modified by Ta included
increases in residual volume and lavageable potassium, glucose, urea,
and ascorbic acid. There was a progressive decrease in lavageable
uric acid with exposure at 34 degrees C. Most effects were attenuated
during the 5 exposure days and/or returned to normal levels after 7
air recovery days regardless of prior O3 exposure or Ta. It is
possible that Ta-induced changes in metabolic rate may have altered
ventilation and, therefore, the ozone doses among rats exposed at the
three different Ta levels.
Received 25 January 1996; accepted in final form 10 June 1996.
APS Manuscript Number A90-6.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 28 June 96