The effect of repeated ozone exposures on inflammatory markers in bronchoalveolar lavage fluid and mucosal biopsies

The aim of this study was to investigate the cellular and biochemical event s associated with repeated exposures to ozone. Twenty-three healthy subject s underwent single exposures to 200 ppb ozone and to filtered air (FA), as well as repeated exposures to 200 ppb ozone on 4 consecutive days, each for 4 h of intermittent exercise. Bronchoalveolar lavage was performed and muc osal biopsies were taken 20 h after the single or the last of the repeated exposures. As compared with FA, the single exposure to ozone caused a decre ase in FEV1, an increase in the percentages of neutrophils and lymphocytes, the concentrations of total protein, IL-6, IL-8, reduced glutathione, urat e, and ortho-tyrosine in BAL fluid (BALF), but no changes in the cellular c omposition of biopsy. After the repeated exposure, the effect on lung funct ion was abolished and differential cell counts in BALF were not significant ly different from those after FA. However, the concentrations of total prot ein, IL-6, IL-8, reduced glutathione, and ortho-tyrosine were still increas ed. IL-10 could only be detected in BALF after repeated ozone exposures. Fu rthermore, macroscopic scores for bronchitis, erythema, and hypervulnerabil ity of airway mucosa were increased, as well as numbers of neutrophils in b ronchial mucosal biopsies. Our data demonstrate that airway inflammation pe rsists after repeated ozone exposure, despite attenuation of some inflammat ory markers in BALF and adaptation of lung function.