title: Decidual neutrophil infiltration is not required for preterm birth in a mouse model of infection-induced preterm labor.
abstract: Parturition is associated with a leukocyte influx into the intrauterine tissues; however, the exact role these leukocytes play in the onset of labor remains unclear. Neutrophil infiltration of the uteroplacental tissues has been particularly associated with infection-associated preterm labor (PTL) in both women and mouse models. In this study, we investigated the role of neutrophils in a mouse model of infection-induced PTL. Intrauterine administration of LPS on day 17 of gestation resulted in a 7-fold increase in the number of decidual neutrophils compared with control mice receiving PBS (p < 0.01; n = 8-11). We hypothesized that neutrophil influx is necessary for PTL and that neutrophil depletion would abolish preterm birth. To test this hypothesis, mice were depleted of neutrophils by treatment with anti-Gr-1, anti-Ly-6G, or the appropriate IgG control Ab on day 16 of gestation prior to LPS on day 17 (n = 6-7). Successful neutrophil depletion was confirmed by flow cytometry and immunohistochemistry. Neutrophil depletion with Gr-1 resulted in reduced uterine and placental Il-1β expression (p < 0.05). Neutrophil depletion with Ly-6G reduced uterine Il-1β and Tnf-α expression (p < 0.05). However, neutrophil depletion with either Ab did not delay LPS-induced preterm birth. Collectively, these data show that decidual neutrophil infiltration is not essential for the induction of infection-induced PTL in the mouse, but that neutrophils contribute to the LPS-induced inflammatory response of the uteroplacental tissues.
authors: Medical Research Council Centre for Reproductive Health, University of Edinburgh, Queen's Medical Research Institute, Edinburgh EH16 4TJ, United Kingdom;
authors: Sara F
authors: SF
authors: Rinaldi
authors: Rob D
authors: RD
authors: Catalano
authors: Jean
authors: J
authors: Wade
authors: Adriano G
authors: AG
authors: Rossi
authors: Jane E
authors: JE
authors: Norman
mesh_terms: D000818:Animals; D003656:Decidua / Q000276:immunology* / Q000473:pathology; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D007239:Infections / Q000276:immunology / Q000473:pathology; D053583:Interleukin-1beta / Q000276:immunology; D008070:Lipopolysaccharides / Q000633:toxicity*; D051379:Mice; D020556:Neutrophil Infiltration / Q000187:drug effects*; D009504:Neutrophils / Q000276:immunology* / Q000473:pathology; D007752:Obstetric Labor, Premature / Q000139:chemically induced* / Q000276:immunology / Q000473:pathology; D011247:Pregnancy
chemical_list: D053583:Interleukin-1beta; D008070:Lipopolysaccharides; C440499:lipopolysaccharide, Escherichia coli O111 B4