Free radical research
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Free radical research · Jan 1998
Randomized Controlled Trial Clinical TrialNasal cavity lining fluid ascorbic acid concentration increases in healthy human volunteers following short term exposure to diesel exhaust.
To determine if diesel exhaust (DE) exposure modifies the antioxidant defense network within the respiratory tract lining fluids, a randomized, single blinded, crossover control study using nasal lavage and flexible video bronchoscopy with bronchial and bronchoalveolar lavage was performed. Fifteen healthy, non-smoking, asymptomatic subjects were exposed to filtered air or diluted diesel exhaust (300mg m(-3) particulates, 1.6ppm nitrogen dioxide) for one hour on 2 separate occasions, at least three weeks apart. To examine the kinetics of any DE-induced antioxidant reactions, nasal lavage fluid and blood samples were collected prior to, immediately after, and 5 1/2 hours post exposure. ⋯ DE exposure did not influence plasma, bronchial wash, or bronchoalveolar lavage antioxidant concentrations and no change in MDA or protein carbonyl concentrations were found. The physiological response to acute DE exposure is an increase in the level of ascorbic acid in the nasal cavity. This response appears to be sufficient to prevent further oxidant stress in the respiratory tract of normal individuals.