| Abstract: | Wiester, Mildred J., William P. Watkinson, Daniel L. Costa,Kay M. Crissman, Judy H. Richards, Darrell W. Winsett, and Jerry W. Highfill. Ozone toxicity in the rat. III. Effect of changes inambient temperature on pulmonary parameters. J. Appl.Physiol. 81(4): 1691-1700, 1996. Pulmonarytoxicity of ozone (O3) wasexamined in adult male Fischer 344 rats exposed to 0.5 parts/millionO3 for either 6 or 23 h/day over 5 days while maintained at an ambient temperature(Ta) of either 10, 22, or34°C. Toxicity was evaluated by using changes in lung volumes andthe concentrations of constituents of bronchoalveolar lavage fluid thatsignal lung injury and/or inflammation. Results indicated thattoxicity increased as Tadecreased. Exposures conducted at 10°C were associated with thegreatest decreases in body weight and total lung capacity and thegreatest increases in lavageable protein, lysozyme, alkaline phosphatase activity, and percent neutrophils.O3 effects not modified byTa included increases in residualvolume and lavageable potassium, glucose, urea, and ascorbic acid.There was a progressive decrease in lavageable uric acid with exposureat 34°C. Most effects were attenuated during the 5 exposure daysand/or returned to normal levels after 7 air recovery days,regardless of prior O3 exposure orTa. It is possible thatTa-induced changes in metabolic rate may have altered ventilation and, therefore, theO3 doses among rats exposed at thethree different Ta levels. |
