The effect of hexafluorocyclobutene on rat bronchoalveolar lavage fluid surfactant phospholipids and alveolar type II cells

Hexafluorocyclobutene (HFCB), a reactive organohalogen gas, causes overwhel ming pulmonary oedema. We investigated its effect on the rat lung surfactan t system, comparing its action on type II pneumocytes with air-exposed rats . The inflammatory cell population and protein content of bronchoalveolar l avage fluid was analysed following exposure to air or HFCB (LCt(30)). Six r at lung phospholipids were measured by high-performance liquid chromatograp hy, following solid phase extraction (SPE) from lavage fluid. Transmission electron microscopy (TEM) was used to visualise effects ion alveolar type I I cell ultrastructure. HFCB caused changes in cell populations and increase d lavage fluid protein compared to controls, suggesting a permeability oede ma. Changes in the total amount and percentage composition (sustained decre ase in phosphatidylglycerol and phosphatidylcholine) of surfactant phosphol ipids also occurred. TEM observations indicated no direct ultrastructural d amage to the type II cells, but showed initial, rapid release of surfactant into the alveolar space. HFCB altered the surfactant system in a manner si milar to that shown following another reactive organohalogen gas, perfluoro isobutene (PFIB), but differently to that after phosgene. These differences suggest different mechanisms of action even though pulmonary oedema is the final injury far all gases. Better knowledge of the mechanisms involved wi ll improve prospects for prophylactic/therapeutic intervention.