Antenatial infection in the rabbit impairs post-natal growth and lung alveolarisation

Clinical and experimental studies indicate an association between chorioamnionitis and bronchopulmonary dysplasia in preterm infants. The present authors hypothesised that, in the rabbit, antenatal infection may impair lung development after birth, despite effective maternal antibiotic therapy. Pregnant rabbits received an intra-uterine inoculation of 10(3) Escherichia coli colony forming units or vehicle at the end of gestation (day 29). Intravenous ceftriaxone therapy was initiated 8 h after inoculation for a period of 8 days. Pups born between 60 and 84 h after inoculation were kept with their mother until sacrifice on days 0, 1, 5, 8 and 15. Blood cultures from antenatally infected animals were sterile at birth. Postnatal growth was significantly impaired by day 8. Lung morphometry showed a significant decrease of alveolar surface density and interstitial density, with a significant increase of alveolar airspace volume, indicating impaired alveolarisation for the first 2 weeks of postnatal life. Inflammatory and apoptotic processes were not detected in the lung at birth or subsequently. Intra-uterine infection in rabbits is, therefore, responsible for concomitant postnatal growth retardation and abnormal pulmonary development despite early and effective antenatal antibiotic therapy. This may constitute an alternative model to study the consequences of antenatal infection on postnatal growth and lung development.