LUNG-FUNCTION IN PREMATURE LAMBS AND RABBITS TREATED WITH A RECOMBINANT SP-C SURFACTANT

We evaluated the efficacy of a recombinant surfactant protein-C (rSP-C ) surfactant in vitro and in vivo, using ventilated preterm lambs and rabbits. The surface tension measured with a Wilhelmy balance of the r SP-C surfactant was lower than the surface tension of natural sheep su rfactant (containing SP-B and SP-C). The rSP-C and natural surfactants were equivalently sensitive to inhibition by plasma. Over a 5-h study period, lambs treated with 100 mg/kg rSP-C and natural surfactants at birth had similar Pco(2), lung mechanics, and FRC values. Indicators of injury also were not different. In preterm rabbits ventilated with 3 cm H2O positive end-expiratory pressure (PEEP), similar compliance r esponses were measured for the rSP-C and natural surfactant. Large-agg regate surfactants recovered from alveolar washes of the lambs treated with rSP-C or natural surfactant retained their function when tested in preterm rabbits. In conclusion, the rSP-C surfactant was effective in preterm animals with surfactant deficiency.