Alteration of ozone-induced airway permeability by oxygen metabolites and antioxidants

This study determined the interactive effects of O3 and enzymatically-generated oxidants and antioxidants in the lung. Rats treated with dimethylthiourea (DMTU) or H2O2, generated by glucose/glucose oxidase, were exposed for 2 h to 0.6 or 0.8 ppm O3. A significant increase in the flux of total albumin in the bronchoalveolar lavage (BAL) and a concomitant elevation in the transport of 99mTc-diethylenetriaminepentaacetate (99mTc-DTPA) from trachea to blood occurred after O3 exposure. Pretreatment of rats with DMTU prevented the albumin flux in the BAL. Intratracheal instillation of glucose/glucose oxidase produced a localized response in trachea, but it did not affect the broncho-alveolar permeability. The results demonstrate an additive effect of O3 and an enzymatically-generated oxidant, and an antagonistic effect of an antioxidant in rats exposed to O3. The observations support the suggestion that a balance of oxidant-antioxidant system may be critical in maintaining respiratory integrity following O3 exposure.