| Effects of Multiday Exposure to Ozone on Airway Inflammation as Determined Using Sputum Induction Jeffrey Ratto,1 Hofer Wong,2 Jane Liu,2 John
Fahy,2 Homer Boushey,2 Colin Solomon,1,3 and
John Balmes1,2,3 1Lung Biology Center, 2Division of Pulmonary and Critical
Care Medicine, and 3Northern California Center for Occupational
and Environmental Health, University of California San Francisco, San Francisco,
California, USA Abstract
Single short-term exposures to ozone are known to cause acute changes in pulmonary function and neutrophilic airway inflammation. The respiratory health effects of repeated exposures are not as well studied. Pulmonary function decrements are known to attenuate, but it is less clear how injury and inflammation are affected. Using sputum induction (SI) to sample respiratory tract lining fluid after single- and multiday exposures, we designed a study to test the hypothesis that neutrophils would increase after multiday exposure compared with single-day exposure. In a randomized, crossover design, 15 normal healthy subjects were exposed to O3 (0.2 ppm) under two conditions: for 4 hr for 1 day (1D) and for 4 hr for 4 consecutive days (4D) . Pulmonary function testing was performed immediately before and after each 4-hr exposure. The SI was performed 18 hr after the end of the 1D and 4D conditions. The symptom and pulmonary function data followed a pattern seen in other multiday O3 exposure studies, with the greatest changes occurring on the second day. In contrast to previous studies using bronchoalveolar lavage, however, there was a significant increase in the percentage of neutrophils and a significant decrease in the percentage of macrophages after the 4D condition compared with the 1D condition. Given that SI likely samples proximal airways better than distal lung, these results add to the body of evidence that differential airway compartmental responses to O3 occur in humans and other species. Key words: airway inflammation, multiday exposure, ozone, proximal airways, sputum induction. Environ Health Perspect 114:209-212 (2006) . doi:10.1289/ehp.8341 available via http://dx.doi.org/ [Online 29 September 2005]
Address correspondence to J. Balmes, University of California San Francisco, Box 0843, San Francisco, CA 94143-0843 USA. Telephone: (415) 206-8950. Fax: (415) 206-8949. E-mail: jbalmes@itsa.ucsf.edu This work was supported by the California Air Resources Board (93-303) and the National Institutes of Health (R01 ES08970) . The authors declare they have no competing financial interests. Received 19 May 2005 ; accepted 29 September 2005. The full version of this article is available for free in HTML or PDF formats. |
