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 hearing 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 mu mol/kg; 10 weeks of Ureaplasina exposure, 7.43 +/- 3.0 mu mol/kg; P < .001) and surfactant protein messenger RNA expression. Conclusion: Long-term exposure to ureaplasmas in amniotic fluid alters ovine fetal development. (c) 2005 Elsevier Inc. All rights reserved.