Maternal and intra-amniotic corticosteroid effects on lung morphometry in preterm lambs.
We investigated the effects of intra-amniotic (IA) betamethasone or budesonide injections on lung structure 2 or 7 d after treatment in preterm fetal sheep. Pregnant ewes received intra-amniotic betamethasone (2 mg/kg fetal weight), budesonide (2 mg/kg), saline or maternal intramuscular betamethasone (0.5 mg/kg maternal weight), or saline. Lambs were delivered 2 or 7 d later at 124 d of gestation. Morphometric analysis was conducted on the right upper lung lobe. Intra-amniotic corticosteroids, 2 or 7 d before delivery, resulted in higher average alveolar volumes than controls (2 d: 25%-35%, 7d: 15%-25%). All corticosteroid treatments resulted in thinning of alveolar walls 7 d after treatment and a higher proportion of alveolar ducts and a lower alveolar wall fraction relative to controls 2 or 7 d after treatment. The changes in structural lung indices correlated with the improved lung function at 2 d. Structural lung indices and increased surfactant correlated with the improved lung function at 7 d. Similar structural changes induced by intra-amniotic corticosteroids and maternal intramuscular betamethasone were associated with improvements in lung function at 2 and 7 d.
Polglase
Graeme R
GR
School of Women's and Infants' Health, The University of Western Australia, Crawley, Western Australia, 6009, Australia. graeme.polglase@uwa.edu.au
Nitsos
Ilias
I
Jobe
Alan H
AH
Newnham
John P
JP
Moss
Timothy J M
TJ
D000653:Amniotic Fluid / Q000737:chemistry; D000818:Animals; D001623:Betamethasone / Q000008:administration & dosage / Q000494:pharmacology; D019819:Budesonide / Q000008:administration & dosage / Q000494:pharmacology; D004333:Drug Administration Routes; D005260:Female; D005325:Fetal Organ Maturity; D005938:Glucocorticoids / Q000008:administration & dosage / Q000494:pharmacology; D008168:Lung / Q000033:anatomy & histology* / Q000187:drug effects* / Q000196:embryology / Q000502:physiology; D011247:Pregnancy; D011256:Pregnancy Outcome; D034561:Sheep, Domestic
D005938:Glucocorticoids; D019819:Budesonide; D001623:Betamethasone