Oxidant-mediated ciliary dysfunction. Possible role in airway disease.

The effects of reactive species of oxygen on the airway are not well known. This study examined the effects of hydrogen peroxide (H2O2) on the structure and function of the airway epithelium. Tracheal rings were prepared from 200 g male rats. Damage to the airway epithelium was assayed by monitoring the ciliary beat frequency, the release of 51Cr, and histology. H2O2 at concentrations of 1.0 mM and above caused a very rapid decrease in ciliary beat frequency. After ten minutes' exposure to 1.0 mM, the ciliary beat frequency was 72 +/- 20 percent of control. Release of 51Cr was a less sensitive measure with significant release occurring after four hours of exposure to ciliotoxic concentrations of H2O2. Histologic changes were not evident within the experimental time period. All toxic effects of H2O2 were completely blocked by catalase. This study shows that H2O2 causes a rapid decline in ciliary activity and suggests that oxidant-mediated ciliary dysfunction could play a role in the pathogenesis of airway disease. The ciliary beat frequency provides a sensitive, physiologically relevant parameter for the in vitro study of these diseases.