title: Differences in extracellular matrix remodeling in the placenta of mares that retain fetal membranes and mares that deliver fetal membranes physiologically.
abstract: BACKGROUND
  In mammals, placenta separation at term may involve degradation of the extracellular matrix by matrix metalloproteinases (MMPs). The activity of MMPs is modulated by TIMPs. We hypothesized that the placentas of mares that deliver fetal membranes physiologically and those that retain fetal membranes (FMR) differ in terms of histology; mRNA expression of MMP-2 and MMP-9; protein expression of MMP-2, MMP-9, and TIMP-2; and the potential activity of both MMPs.
  
  
  METHODS
  Placenta biopsies were taken from mares (n = 9; 4 FMR, 5 controls) immediately after foal expulsion. Retention was defined as failure to expel all fetal membranes within 3 h of expulsion. All mares were monitored for time of expulsion. The degree of allantochorial/endometrial adhesion was determined in FMR mares, and biopsies from all mares were histologically examined. mRNA expression, protein immunolocalization, protein amount and potential enzyme activity were determined with RT-PCR, immunohistochemistry, Western Blotting and zymography, respectively.
  
  
  RESULTS
  FMR mares had strong to extremely strong allantochorial/endometrial adhesion, and significantly more connective tissue in the allantochorial villi than controls. The range of MMP-2 mRNA expression levels was more than 13 times greater in FMR mares than in controls. Protein content of both MMPs and TIMP-2 differed significantly between groups. The range of potential MMP-2 and MMP-9 activity was larger in FMR mares, and MMP-2 potential activity was 1.4 times higher in controls (P = 0.02).
  
  
  CONCLUSIONS
  These results indicate differences in extracellular matrix remodeling in FMR mares and controls, and suggest dysregulation of MMP expression and activation in FMR mares.
authors: Department of Animal Reproduction with Clinic, Faculty of Veterinary Medicine, University of Warmia and Mazury, ul. Oczapowskiego 14, 10-719 Olsztyn, Poland. Electronic address: anna.rapacz@uwm.edu.pl.
authors: A
authors: A
authors: Rapacz-Leonard
authors: Department of Biochemistry, Faculty of Veterinary Medicine, University of Life Sciences, ul. Akademicka 12, 20-033 Lublin, Poland.
authors: M
authors: M
authors: Kankofer
authors: University of Warmia and Mazury, Oczapowskiego 14, 10719 Olsztyn, Poland.
authors: M
authors: M
authors: Leonard
authors: Department of Biochemistry, Faculty of Veterinary Medicine, University of Life Sciences, ul. Akademicka 12, 20-033 Lublin, Poland.
authors: J
authors: J
authors: Wawrzykowski
authors: Department of Animal Reproduction with Clinic, Faculty of Veterinary Medicine, University of Warmia and Mazury, ul. Oczapowskiego 14, 10-719 Olsztyn, Poland.
authors: M
authors: M
authors: Dąbrowska
authors: Department of Animal Reproduction with Clinic, Faculty of Veterinary Medicine, University of Warmia and Mazury, ul. Oczapowskiego 14, 10-719 Olsztyn, Poland.
authors: A
authors: A
authors: Raś
authors: Department of Pathological Anatomy, Faculty of Veterinary Medicine, University of Warmia and Mazury, ul. Oczapowskiego 13, 10-719 Olsztyn, Poland.
authors: K
authors: K
authors: Paździor-Czapula
authors: Department of Animal Reproduction with Clinic, Faculty of Veterinary Medicine, University of Warmia and Mazury, ul. Oczapowskiego 14, 10-719 Olsztyn, Poland.
authors: T
authors: T
authors: Janowski
mesh_terms: D000818:Animals; D015153:Blotting, Western; D016022:Case-Control Studies; D003238:Connective Tissue / Q000473:pathology; D004717:Endometrium / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism; D005321:Extraembryonic Membranes / Q000201:enzymology* / Q000473:pathology; D005260:Female; D006736:Horses; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D010920:Placenta / Q000473:pathology; D018457:Placenta, Retained / Q000201:enzymology* / Q000473:pathology; D011247:Pregnancy; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000378:metabolism*
chemical_list: D019716:Tissue Inhibitor of Metalloproteinase-2; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9
keywords: Gelatinases; Horse; MMP-2; MMP-9; Retained placenta; TIMP-2