Surfactant alterations following acute bleomycin and hyperoxia-induced lung damage.

Hamsters treated with 0.5 U/kg intratracheal bleomycin and exposed for 24 h to 80% O2 develop acute respiratory failure 72 h after treatment. To examine indirectly the lung epithelial type II cell changes, alterations in pulmonary surfactant was measured. Presence and amount of dipalmitoyl phosphatidyl choline (DDPC) and sphingomyelin (SM) were measured, and the DPPC/SM ratio was determined in brochoalveolar lavage samples from treated and control animals 24, 48, 72, and 96 h after treatment. Hamsters treated with bleomycin and O2 had a significantly decreased DPPC/SM ratio at 72 h, which is the time of onset of respiratory failure. The decreased DPPC/SM ratio may reflect type II cell damage and inhibition of surfactant function by the edema fluid.