title: Placental lesions caused by experimental infection of Sprague-Dawley rats with Mycoplasma pulmonis.
abstract: OBJECTIVE
  Sprague-Dawley (SD) rats infected during pregnancy with Mycoplasma pulmonis display adverse pregnancy outcomes that are similar to those observed in women with chorioamnionitis and may provide a good model system for this disease. The placental lesions caused by this microorganism, however, have not been thoroughly characterized.
  
  
  METHODS
  Rats were infected with 10(7) colony-forming units (CFU) M. pulmonis or vehicle control on gestation day (gd) 14 and were euthanized on gd 16-18. Tissues were fixed in 10% neutral buffered formalin, embedded in paraffin, sectioned at 4 microm, and stained with hematoxylin and eosin (H & E). The slides were coded and examined by a blinded pathologist using light microscopy.
  
  
  RESULTS
  Infection with M. pulmonis was associated with necrosis of trophoblast giant cells at gd 18. Significantly more neutrophils were observed in the decidual region of the apex of the placenta in M. pulmonis infected animals. The vast majority of neutrophils, however, were observed in the decidua in the lateral regions of the placenta and in the adjacent endometrium.
  
  
  CONCLUSIONS
  Infection of SD rats with M. pulmonis resulted in histological placentitis similar to that described in deciduitis of humans and represents a good model system for investigations into the pathophysiology of intrauterine infection. The influx of neutrophils seems to migrate from the endometrium towards the lateral regions of the placenta near Reichert's membrane and the divergence of the parietal yolk sac.
authors: Department of Pathobiology, University of Florida, Gainesville, FL, USA. mpeltier@hci.utah.edu
authors: Morgan R
authors: MR
authors: Peltier
authors: Lauren J
authors: LJ
authors: Richey
authors: Mary B
authors: MB
authors: Brown
mesh_terms: D000818:Animals; D005260:Female; D020567:Fetal Weight; D005333:Fetus / Q000382:microbiology; D009175:Mycoplasma Infections / Q000382:microbiology / Q000473:pathology*; D045803:Mycoplasma pulmonis; D009504:Neutrophils / Q000737:chemistry; D010920:Placenta / Q000737:chemistry / Q000382:microbiology / Q000473:pathology*; D010922:Placenta Diseases / Q000382:microbiology / Q000473:pathology*; D011247:Pregnancy; D011256:Pregnancy Outcome; D051381:Rats; D017207:Rats, Sprague-Dawley