Surfactant protein C in fetal and ventilated preterm rabbit lungs.
The developing lung contains surfactant protein (SP) C mRNA levels comparable to term values before mature type II cells and alveolar surfactant lipids are detectable. Estimates of the amount of mature SP-C in the alveolar lavages of preterm lungs are not available. We used an antibody to a recombinant human SP-C to measure the amount of SP-C in alveolar lavages of preterm fetal rabbits, ventilated preterm rabbits, and term rabbits. The amounts of SP-C were compared with the amounts of saturated phosphatidylcholine (Sat PC). Median Sat PC amounts increased about 680-fold, and median SP-C values increased by over 5,000-fold in alveolar washes from 27 days gestation to term. There was no increase in Sat PC or SP-C with ventilation at 27 and 28 days gestation, but ventilation increased both Sat PC and SP-C at 29 days gestation. The molar percent of SP-C relative to Sat PC also increased with gestational age and with ventilation at 29 days gestation. proSP-C was abundant in a membrane fraction from lung tissue at 27 and 28 days gestation when minimal mature SP-C was detected in alveolar washes. At 29 days and at term, proSP-C decreased in membrane fractions. The preterm lung that is surfactant lipid deficient is also severely deficient in mature SP-C.
Ross
G F
GF
Children's Hospital Medical Center, Division of Pulmonary Biology, Cincinnati, Ohio 45229-3039, USA.
Ikegami
M
M
Steinhilber
W
W
Jobe
A H
AH
D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D005260:Female; D005333:Fetus / Q000737:chemistry; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D010713:Phosphatidylcholines / Q000032:analysis; D011247:Pregnancy; D011510:Proteolipids / Q000032:analysis*; D011650:Pulmonary Alveoli / Q000737:chemistry* / Q000196:embryology*; D011663:Pulmonary Surfactants / Q000032:analysis*; D011817:Rabbits; D012121:Respiration, Artificial; D012127:Respiratory Distress Syndrome, Newborn / Q000503:physiopathology*; D013990:Tidal Volume
D010713:Phosphatidylcholines; D011510:Proteolipids; D011663:Pulmonary Surfactants