Intra-amniotic endotoxin induces IL-1, causes chorioamnionitis, lung inflammation, lung injury and lung maturation in preterm lambs. Intra-amniotic IL-1α also causes chorioamnionitis, lung inflammation and lung maturation. We asked if IL-1α effects on the preterm lung are mediated by direct signaling to the lung rather than by indirect effects from the chorioamnionitis. To study IL-1 effects independently of chorioamnionitis, the lungs and the amniotic fluid were surgically separated in fetal sheep by diverting fetal lung fluid via a tracheostomy tube to a sialastic bag. A mini-osmotic pump delivered an intratracheal infusion of recombinant sheep IL-1α (10 μg) or saline (control) over 24 h. Preterm lambs were delivered 1d or 7d after the start of the infusion at 124d gestational age (Term = 150d). IL-1α recruited inflammatory cells and increased pro-inflammatory cytokine mRNA expression in the fetal lungs. Compared with controls, IL-1α did not alter lung antioxidant enzyme activity or alveolar numbers. IL-1α had minimal effects on the mRNA or protein expression of proteins essential for vascular development. IL-1α induced large increases in alveolar surfactant saturated phosphatidylcholine and increased lung gas volumes. Lung inflammation and maturation result from direct exposure of the fetal lung to a single cytokine - IL-1α.
|Original language||English (US)|
|Number of pages||5|
|State||Published - Sep 2006|
ASJC Scopus subject areas
- Pediatrics, Perinatology, and Child Health