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EFFECT OF ANTIOXIDANT SUPPLEMENTATION ON OZONE-INDUCED LUNG INJURY IN HUMAN SUBJECTS
Citation:
Samet, J M., D. H. Horstman, S. Steck, L. Arab, P A. Bromberg, M. Levine, W F. McDonnell, AND R B. Devlin. EFFECT OF ANTIOXIDANT SUPPLEMENTATION ON OZONE-INDUCED LUNG INJURY IN HUMAN SUBJECTS. AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE. American Thoracic Society, New York, NY, 164(1):819-825, (2001).
Description:
Epidemiological, in vitro and animal studies suggest that dietary antioxidants can modulate the cellular and physiologic effects of ozone (O3) inhalation in humans. To determine whether antioxidants can influence human susceptibility to O3-induced changes in lung function and airway inflammation, 31 healthy non-smoking adults (18-35 yrs old) were placed on a diet low in ascorbate for 3 weeks. Subjects underwent extensive dietary screening and kept daily food records. After one week, subjects were exposed to filtered air for 2 hr while undergoing intermittent moderate exercise (20 L/min/m2) followed by bronchoalveolar lavage (BAL), and were randomly assigned to receive either placebos or 250 mg vitamin C, 50 IU a-tocopherol and 12 oz vegetable cocktail daily for 2 weeks. Subjects were then exposed to 0.4 ppm O3 for 2 hr and underwent a second BAL. On the day of the O3 exposure, supplemented subjects were found to have significantly increased levels of plasma ascorbate, tocopherols and carotenoids when compared to the placebo group. Pulmonary function testing showed that O3-induced reductions in FEV1 and FVC were 30.2 and 23.5 % smaller, respectively, in the supplemented cohort. In contrast, the inflammatory response to O3 inhalation, as represented by the percent PMN and the concentration of IL-6 recovered in the BAL fluid 1 hour after O3 exposure was not different between the two groups. These data suggest that dietary antioxidants may confer some protection against O3-induced pulmonary function decrements but may not alter inflammatory responses in normal humans.