Antenatal inflammation and the developing lamb lung

K. Willet, R. Collins, A. Jobe, M. Ikegami, J. Newnham, T. Moss, P. Sly

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Background and aims: Antenatal inflammation has been linked to the development of Neonatal Chronic Lung Disease but may also decrease the risk of Respiratory Distress Syndrome by accelerating fetal lung maturation. We recently found that intra-amniotic (IA) injection of lipopolysaccharide (LPS), a potent pro-inflammatory stimulus, led to improved postnatal lung function and increased alveolar surfactant in preterm lambs when given 7 days prior to delivery. In the present study we examined the impact of injecting LPS early in gestation (during the glandular or canalicular stage of lung development) on postnatal lung function in preterm lambs. Methods: Date bred Merino ewes received LPS (20mg E. coli endotoxin) or saline at 60 (40%), 80 (53%) or 100 days (67%) gestation by ultrasound guided IA injection. Lambs were delivered by cesarean section at 125 days gestation (term = 150 days) and lung function was monitored during 40 minutes of conventional mechanical ventilation. Results: Lambs exposed to LPS at 80 days were able to be ventilated at lower peak inspiratory pressure (PIP) and had lower resistance (Rrs) and elastance (Ers, inverse of compliance) than control animals (P<0.05). Lambs exposed to LPS at 60 days also had decreased Rrs (P<0.05). Both 60d and lOOd LPS animals showed a significant increase in %E2, a measure of over-distension during mechanical ventilation. Despite the increase in %E2, tidal volume and PIP in 60d and lOOd LPS animals were similar to controls. Conclusions: Exposure to LPS during the glandular or canalicular stage of lung development significantly improves postnatal lung function in preterm lambs. However, the lungs appear to be more easily over-distended during mechanical ventilation, suggesting that LPS may impact on inherent structural characteristics of the developing lung.

Original languageEnglish
Issue numberSUPPL. 1
Publication statusPublished - 1 Dec 2001
Externally publishedYes


  • Antenatal inflammation
  • Fetal lung development
  • Preterm delivery

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