Restoration of lung compliance with calf lung surfactant extract and a surfactant analog in an in situ model of surfactant deficiency in rats

We have developed a standardized in situ lung surfactant deficiency model in the rat by using a single bronchoalveolar lavage (BAL). The purpose of this study was to assess the usefulness of surfactants and surfactant analogs in terms of their in vivo physiological properties. Calf lung surfactant extract (CLSE) was shown to improve lung compliance in a dose-dependent manner in this surfactant deficiency model when administered intratracheally immediately after BAL. In addition, CLSE formulated with a diether (palmityl) phosphonolipid surfactant analog significantly improved the compliance post-BAL as compared to CLSE alone. We propose that this in situ bioassay may be useful for the assessment of physiological capabilities of surfactants, surfactant analogs and surfactant formulations.