Modulation of LPS-induced chorioamnionitis by ureaplasma parvum in sheep chorioamnionitis in sheep

ABSTRACT Objective: Ureaplasma parvum colonization in the setting of polymicrobial flora is common in women with chorioamnionitis, and is a risk factor for preterm delivery and neonatal morbidity. We hypothesized that ureaplasma colonization of amniotic fluid will modulate chorioamnionitis induced by E.coli lipopolysaccharide (LPS). Methods: Sheep received intra-amniotic (IA) injections of media (control) or live ureaplasma either 7 or 70d before delivery. Another group received IA LPS 2d before delivery. To test for interactions, U.parvum exposed animals were challenged with IA LPS, and delivered 2d later. All animals were delivered preterm at 125±1 day gestation. Results: Both IA ureaplasmas and LPS induced leukocyte infiltration of chorioamnion. LPS greatly increased the expression of pro-inflammatory cytokines and myeloperoxidase in leukocytes, while ureaplasmas alone caused modest responses. Interestingly, 7d but not 70d ureaplasma exposure significantly downregulated LPS induced pro-inflammatory cytokines and myeloperoxidase expression in the chorioamnion. Conclusion: U.parvum can suppress LPS induced experimental chorioamnionitis.