[The effect of a short-term SO2 exposure on the respiratory function of sensitized non-anesthetized rabbits]

Exposure to atmospheric pollutants may adversely effect respiratory function. Asthmatics as well as persons with airway hyperresponsiveness are more sensitive to atmospheric pollutants than normal persons. So we examined the influence of bovine serum albumin (BSA) sensitization on changes of respiratory function induced by SO2 exposure of 10 min. in non-anesthetized rabbits. Furthermore the effect of SO2-exposure on changes of respiratory function induced by secondary BSA-sensitization was tested. Respiratory flow (VR), tidal volume (Vt), respiratory pressure (PM), respiratory resistance (RL = PM/VR), and dynamic Compliance (Cdyn = Vt/PM) were examined. Our data showed that SO2-exposure marginally reduced respiratory flow and increased respiratory resistance but did not change tidal volume and dynamic compliance. Reduction of respiratory flow induced by SO2-exposure was independent from BSA-sensitization in the first week, however increase of respiratory resistance was slightly higher in BSA sensitized than in non-sensitized rabbits after SO2-treatment. Secondary BSA-sensitization reduced respiratory flow independent from SO2-inhalation and increased respiratory resistance stronger in SO2 treated than in non-treated rabbits. Tidal volume and dynamic compliance also increased after secondary sensitization. The increase of dynamic compliance was significantly higher in non-treated than in SO2 treated rabbits, but it was not so evident in case of tidal volume.