Pulmonary inflammation without bronchial hyperresponsiveness in vivo or invitro after sephadex instillation in pigs

1. In rodent models, Sephadex produces pulmonary inflammation that may be a ssociated with bronchial hyperresponsiveness. In the present study we exami ned whether Sephadex-induced inflammation altered airway narrowing in pigs. 2. Twenty millilitres of 10 mg/mL Sephadex suspension was instilled twice i ntratracheally into anaesthetized pigs (days 1 and 7 of a 9 day study). In vivo bronchial responsiveness was assessed from the effect of acetylcholine (ACh) aerosol on airways resistance and dynamic compliance before Sephadex instillation and on days 3, 5 and 9. Lung histology and in vitro bronchial responsiveness was assessed on day 9. In vitro responsiveness was assessed by measuring the reduction in flow through perfused 2 mm i.d. bronchial se gments in response to ACh applied luminally and adventitially. 3. Sephadex produced a focal peribronchial granulomatous reaction character ized by the presence of macrophages, eosinophils, neutrophils and giant cel ls. Changes in airway resistance and lung compliance in response to ACh did not change over the study period. The response of perfused bronchial segme nts to luminally or adventitially applied ACh was also unaltered. 4. Sephadex-induced pulmonary inflammation does not alter airway narrowing in vitro nor bronchial hyperresponsiveness in vivo in the pig.