Experimental intrauterine Ureaplasma infection in sheep

OBJECTIVE: Prenatal Ureaplasma spp exposure is associated with preterm birth and modulates the neonates susceptibility to respiratory distress syndrome and bronchopulmonary dysplasia. We hypothesized that intra-amniotic ureaplasmas would cause lung inflammation and alter fetal lung development. STUDY DESIGN: Pregnant ewes bearing singleton fetuses were given an intra-amniotic injection of 20 x 10 6 CFUs of U parvum (serovar 3) or vehicle, either 1, 3, 6, or 10 weeks before the delivery of preterm lambs at 124 days of gestation (n = 4-10 per group) for evaluation of inflammation and fetal lung maturation. RESULTS: Ureaplasmas were recovered from amniotic and fetal lung fluids after intra-amniotic injection. Body weight and umbilical arterial pH were reduced by Ureaplasma exposure for 10 weeks ( P <.05). Ureaplasmas caused progressive lung inflammation and improvements in lung function that were associated with increased surfactant lipids (control, 0.13 +/- 0.02 micromol/kg; 10 weeks of Ureaplasma exposure, 7.43 +/- 3.0 micromol/kg; P <.001) and surfactant protein messenger RNA expression. CONCLUSION: Long-term exposure to ureaplasmas in amniotic fluid alters ovine fetal development.