Alveolar metabolism of natural vs. synthetic surfactants in preterm newborn rabbits.
We compared the recoveries of four surfactant preparations: two natural [term fetal rabbit surfactant (FRS) and adult rabbit surfactant (ARS)] and two commercially available preparations [apoprotein-based Survanta (S) and synthetic Exosurf (E)] from 27-day gestation rabbit pups treated at birth and ventilated up to 120 min. At 5, 60, and 120 min, we measured the recovery of the heavy-aggregate, metabolically active form (H) and the light-aggregate, nonsurface active metabolic breakdown form (L) of alveolar surfactant and determined the phospholipid content and composition of the intracellularly stored lamellar body (LB) pool. Pups treated with FRS had <15% loss of H by 2 h. ARS-treated pups had a >50% loss of H by 1 h, and E- and S-treated pups had approximately 50% loss by 5 min, with a slower rate of continuing loss of up to 80% by 2 h. The major losses of H phospholipid were not explained by the L-form recovery. LB phospholipid significantly increased only in the E-treated pups and only at 2 h. FRS provides a biologically active form (H) of surfactant that appeared to remain in the airway for a significantly longer time than the other surfactant preparations. The unique properties of FRS merit further study.
Allen
V
V
Department of Obstetrics/Gynaecology, Dalhousie University and IWK Grace Health Centre, Halifax, Nova Scotia, Canada.
Oulton
M
M
Stinson
D
D
MacDonald
J
J
Allen
A
A
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D001688:Biological Products; D004338:Drug Combinations; D005233:Fatty Alcohols / Q000378:metabolism*; D005333:Fetus / Q000378:metabolism; D005865:Gestational Age; D010743:Phospholipids / Q000378:metabolism; D010767:Phosphorylcholine; D011092:Polyethylene Glycols / Q000378:metabolism*; D011650:Pulmonary Alveoli / Q000378:metabolism*; D011663:Pulmonary Surfactants / Q000378:metabolism*; D011817:Rabbits; D007507:Therapeutic Irrigation; D013997:Time Factors
D001688:Biological Products; D004338:Drug Combinations; D005233:Fatty Alcohols; D010743:Phospholipids; D011663:Pulmonary Surfactants; D010767:Phosphorylcholine; D011092:Polyethylene Glycols; C047049:dipalmitoylphosphatidylcholine, hexadecanol, tyloxapol drug combination; C072197:beractant