Influence of Exercise on Lung Injury Induced by Ozone and Nitrogen Dioxide

摘要

Three experiments were performed under the study: (1) In the test of exposure duration, rats were exposed to 0.35 ppm O3 while running 15 m/min at 20 percent grade for 0.5, 1.0, 2.0 or 3.0 hours. Slight tissue injuries did not differ from the control for 0.5 and 1.0 hr exposures, but increased by nearly a factor of 2 in 2.0 and 3.0 hr exposures. Moderate tissue injury was first apparent in the 1.0 hr exposure and increased in 2- and 3-hour exposures. (2) In the second experiment, rats were again exposed to 0.35 ppm O3. Exposure duration was adjusted to hold the dose constant. Despite equivalence of effective dose of O3, lesion areas increased with increasing exercise intensity. (3) In the O3 and NO2 interaction experiment, exposure to NO2 (0.6 ppm) alone resulted in no difference from a clean air control. However, NO2 in combination with O3 (.35 ppm) resulted in a greater than expected enhancement of lesion areas induced by O3 alone.