Effect of Antioxidant Supplementation on Ozone-Induced Lung Injury in Human Subjects

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Abstract
To determine whether antioxidants can influence human susceptibility to ozone (O3)-induced changes in lung function and airway inflammation, we placed 31 healthy nonsmoking adults (18 to 35 yr old) on a diet low in ascorbate for 3 wk. At 1 wk, subjects were exposed to filtered air for 2 h while exercising (20 L / min / m2), and then underwent bronchoalveolar lavage (BAL) and were randomly assigned to receive either a placebo or 250 mg of vitamin C, 50 IU of α -tocopherol, and 12 oz of vegetable cocktail daily for 2 wk. Subjects were then exposed to 0.4 ppm O3 for 2 h 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 as compared with those of the placebo group. Pulmonary function testing showed that O3-induced reductions in FEV1 and FVC were 30% and 24% smaller, respectively, in the supplemented cohort. In contrast, the inflammatory response to O3 inhalation, as represented by the percent neutrophils and the concentration of interleukin-6 recovered in the BAL fluid at 1 h after O3 exposure was not different for the two groups. These data suggest that dietary antioxidants protect against O3-induced pulmonary function decrements in humans. Keywords: antioxidants; ozone; human; inflammation