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Pulmonary function in juvenile and young adult rats exposed to low-level NO sub 2 with diurnal spikes

Journal Article · · Journal of Toxicology and Environmental Health; (USA)
OSTI ID:5154687
Pulmonary function was examined for juvenile and young adult Fischer 344 rats that were continuously exposed to NO{sub 2} (0.5, 1.0, or 2.0 ppm) for up to 6 wk. The exposure included twice daily 1-h spikes equal to 3 times the baseline concentration. This spike-to-baseline ratio was chosen to simulate morning and evening urban rush-hour conditions. Juvenile rats were examined after 3 and 6 wk of NO{sub 2} exposure, whereas young adult rats were examined after 1-, 3-, and 6-wk intervals. Lung volumes, compliance, and efficiency of ventilation distribution were evaluated. Lung volumes increased in the juvenile rats after 3- and 6-wk exposures to 1.0 and 2.0 ppm NO{sub 2}, but were unchanged in young adult rats. Lung compliance increased in juvenile rats exposed to 1.0 or 2.0 ppm NO{sub 2} for 3 wk. However, it was unchanged in juvenile rats exposed for 6 wk or in young adult rats exposed for 1 or 3 wk. Compliance decreased in young adult rats exposed to 2.0 ppm NO{sub 2} for 6 wk and was correlated to an overall thickening of alveolar interstitium and septal tissue. However, the observed changes in pulmonary function were marginal and reversible, since lung-function measurements were not different from controls after a 3-wk recovery period.
OSTI ID:
5154687
Journal Information:
Journal of Toxicology and Environmental Health; (USA), Journal Name: Journal of Toxicology and Environmental Health; (USA) Vol. 23:2; ISSN JTEHD; ISSN 0098-4108
Country of Publication:
United States
Language:
English