[Nitric oxide in expired air from rats with experimental bronchitis]

Bronchitis was evoked in 20 rats by SO2 inhalation. Ten rats were exposed to SO2 only, 10 others were exposed to SO2 and treated with heparin simultaneously. The control group consisted of other 10 rats. NO concentration in the air exhaled by all animals was determined. The experiment was carried out in a specially constructed chamber. It lasted 15 weeks. In the group of animals exposed to SO2 only, NO concentration was found beginning from the %th week, with the maximum concentration in the 10th week. In the group of animals exposed to SO2 and treated with heparin NO concentration was much lower than in the above group. NO was not found in the control group. The conclusion is that NO concentration in the exhaled air is a result of bronchial inflammation, and can be decreased during treatment with heparin.