Sequential changes in pulmonary epithelial permeability after birth in term and preterm rabbits.
We assessed sequential changes in the permeability properties of the pulmonary epithelium in spontaneously breathing, newborn term (30 days of gestation) and preterm (28 days) rabbit pups, using the rate of pulmonary clearance of 99mTc-DTPA (MW = 492) as an index of permeability. In term rabbits, clearance was faster at 1 h of age than at hourly timepoints thereafter (p < 0.05). In preterm rabbits, clearance rates measured from 1 to 5 h after birth were not quite significantly different (p = 0.0519) although the trend to slower clearance with increasing time after birth was significant. When term and preterm rabbits were compared, clearance was similar at 1 h after birth but was faster at both 2 and 3 h in the preterm rabbits (p < 0.05). Pulmonary epithelial permeability appears to be increased in the immediate postnatal period and the duration of increased permeability is longer in preterm rabbits. Because lung water content at birth is greater in the preterm rabbits, we speculate that the permeability changes may be associated with clearance of fetal lung liquid.
Jefferies
A L
AL
Department of Paediatrics, Mount Sinai Hospital, University of Toronto, Canada.
Tai
K F
KF
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D001834:Body Water / Q000378:metabolism; D002463:Cell Membrane Permeability; D004848:Epithelium / Q000378:metabolism; D005865:Gestational Age; D007700:Kinetics; D008168:Lung / Q000378:metabolism*; D008657:Metabolic Clearance Rate; D011817:Rabbits; D016284:Technetium Tc 99m Pentetate
D016284:Technetium Tc 99m Pentetate