Surfactant Phospholipid Ontogeny in Fetal Rabbit Lung Lavage and Amniotic Fluid

Abstract

The development of pulmonary surfactant production by the fetal lung is essential for normal lung function at birth. Failure to produce an adequate amount of surfactant is associated with respiratory distress syndrome of the newborn (RDS). Prediction of the risk of RDS is based on the measurement of surfactant phospholipids in amniotic fluid. We have studied the ontogeny of surfactant phospholipids in the fetal rabbit by analyzing samples obtained simultaneously from lung lavage and amniotic fluid during late gestation (days 24–30). A surge in saturated phosphatidylcholine and percent saturation is observed first in lung lavage (day 26), followed 1.5–2.5 days later by a similar increase in amniotic fluid. These findings support the assumption that amniotic fluid surfactant phospholipids reflect the production of surfactant phospholipids in the developing lung.

The pulmonary surfactant system matures upon pipping in the freshwater turtleChelydra serpentina

“…In contrast, the development of the pulmonary surfactant system has been well documented in eutherians. It is one of the last systems to mature, characterized by an increase in extracellular and intracellular phospholipids, enrichment of disaturated phospholipids and the secretion of surfactant proteins in lung and amniotic fluid (Benson et al, 1983;Torday and Nielson, 1981). Both endogenous and exogenous corticosteroids induce synthesis of pulmonary surfactant in the mammalian fetal lung by stimulating enzymes involved in phospholipid synthesis, accelerating lamellar body development and influencing intracellular and extracellular concentrations of surfactant proteins (Merrill and Ballard, 1998).…”