Antioxidant responsiveness in BALB/c mice exposed to ozone.

摘要

BACKGROUND: A single, acute exposure to ozone has been shown to modify the antioxidant defense mechanism in the respiratory tract. OBJECTIVE: The aim of this study was to evaluate the effects of ozone exposure on antioxidant response in BALB/c mice. METHODS: We measured enhanced pause of breathing (Penh) as a marker of airway obstruction using barometric whole-body plethysmography before and after ozone exposure [groups (n = 6): filtered air, 0.12 ppm, 0.5 ppm, 1 ppm, 2 ppm] for 3 h. Antioxidant levels were measured using high-performance liquid chromatography with electrochemical detection in bronchoalveolar lavage (BAL) fluid and lung tissue homogenates. RESULTS: Malondialdehyde concentrations in lung tissue homogenates were significantly increased in the group exposed to 2-ppm ozone compared to the filtered air group. Uric acid and gamma-tocopherol concentrations in BAL fluid were significantly increased in the ozone exposure group compared to the filtered air group (p < 0.01). Uric acid concentrations were increased in a concentration-dependent manner according to ozone concentration to which the animals were exposed. Increases in Penh after ozone exposure were significantly higher in an ozone concentration-dependent manner. The proportion of neutrophils in BAL fluid was significantly higher in the group exposed to 2 ppm than in the filtered air and the group exposed to 0.12 ppm (p < 0.01, respectively). The level of ascorbate correlated with the level of gamma-tocopherol. CONCLUSION: These findings suggest that antioxidant responses may serve as a protective mechanism against a range of oxidants in BALB/c mice exposed to ozone.