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PULMONARY FUNCTION IN JUVENILE AND YOUNG ADULT RATS EXPOSED TO LOW-LEVEL NO2 WITH DIURNAL SPIKES
Citation:
Stevens, M., M. Menache, J. Crapo, F. Miller, AND J. Graham. PULMONARY FUNCTION IN JUVENILE AND YOUNG ADULT RATS EXPOSED TO LOW-LEVEL NO2 WITH DIURNAL SPIKES. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-88/020.
Description:
Pulmonary function was examined in juvenile and young adult Fischer-344 rats continuously exposed to NO2 (0.5, 1.0 or 2.0 ppm) for up to 6 weeks with twice daily 1 hr spikes equal to 3X the baseline concentration. The spike to baseline ratio was chosen to simulate morning and evening urban rush hour conditions. Juvenile rats were examined after 3 and 6 weeks of NO2 exposures, while young adult rats were examined after 1, 3, and 6 week intervals. Lung volumes, compliance, and efficiency of ventilation were evaluated. Lung volumes increased in the juvenile rats after 3 and 6 week exposures to 1.0 and 2.0 ppm, but were unchanged in young adult rats. Lung compliance increased in juvenile rats exposed to 1.0 or 2.0 ppm for 3 weeks, however, was unchanged in juvenile rats exposed for 6 weeks, as well as in the young adult rats exposed for 1 and 3 weeks. Compliance decreased in young adult rats exposed to 2.0 ppm for 6 weeks, and was correlated to an overall thickening of alveolar interstitium and spetal tissues.