Mild Vitamin A Deficiency Delays Fetal Lung Maturation in the Rat

During late pregnancy, the fetal lung stores surfactant in preparation for extrauterine life. Surfactant deficiency, most often due to prematurity, precipitates respiratory distress syndrome (RDS) of the neonate. Although vitamin A (retinol) and retinoic acid have been shown to enhance the synthesis of phospholipid surfactant components, their effect on surfactant-specific proteins is unclear. No attempt has been made to evaluate the consequences of vitamin A restriction on surfactant phospholipid storage or on the expression of the life-essential surfactant protein-B (SP-B). We induced in rats a partial vitamin A deficiency leading to a 30–60% reduction in blood retinol, a status compatible with maintenance of gestation and absence of gross abnormalities in offspring. At term, lung surfactant phospholipids were reduced by 21%, and the major surfactant phospholipid, disaturated phosphatidylcholine (DSPC), was reduced by 27% in vitamin A-deficient (VAD) fetuses. The decrease in surfactant phospholipids and...