Quantification of surfactant pool sizes in rabbit lung during perinatal development.
Methods are presented for the quantitative isolation of surfactants from fetal and newborn rabbit alveolar lavage returns and post-lavaged lung tissue homogenates. The phospholipid content of both fractions progressively increased between 27 days gestation and term (31 days). The tissue-stored fraction increased approximately 16-fold (from 0.48 +/- 0.13 to 7.83 +/- 0.86 mg/g dry lung) and the alveolar fraction more than 30-fold (from 0.08 +/- 0.02 to 2.69 +/- 0.52 mg/g dry lung). Developmental changes in phospholipid composition were also observed. Tissue-stored surfactant was prepared using differential and density gradient centrifugation. Alveolar surfactant was isolated during fetal development as a high-speed pellet following a one-step differential centrifugation. There was little change in the phospholipid content of fetal alveolar lavage supernatant (range 0.12 +/- 0.04 to 0.28 +/- 0.09 mg/g dry lung). By the first postnatal day the phospholipid content of both lavage fractions significantly increased (pellet, 7.51 +/- 1.79; supernatant, 4.01 +/- 1.36 mg/g dry lung) and both were identified as surfactant. This increase in alveolar surfactant was accompanied by an approximately twofold decrease (to 3.81 +/- 1.1 mg/g dry lung) in the tissue-stored fraction. These data provide a quantitative profile of surfactant accumulation and secretion in developing rabbit lung.
D000818:Animals; D000831:Animals, Newborn; D005333:Fetus / Q000378:metabolism; D005865:Gestational Age; D008168:Lung / Q000378:metabolism* / Q000648:ultrastructure; D008854:Microscopy, Electron; D010743:Phospholipids / Q000378:metabolism; D011650:Pulmonary Alveoli / Q000378:metabolism; D011663:Pulmonary Surfactants / Q000378:metabolism*; D011817:Rabbits; D007507:Therapeutic Irrigation
D010743:Phospholipids; D011663:Pulmonary Surfactants