title: Impact of Oral Commensal Bacteria on Degradation of Periodontal Connective Tissue in Mice.
abstract: BACKGROUND
  Innate and adaptive immunosurveillance mechanisms in response to the normal commensal bacteria can affect periodontal innate defense status. However, it is still unclear how commensal bacteria contribute to the inflammatory responses of junctional epithelium (JE) and periodontal connective tissue (PCT). The aim of the present study is to investigate the contribution of commensal bacteria on inflammatory responses in JE and PCT in mice.
  
  
  METHODS
  The periodontal tissue of germ-free (GF) and specific-pathogen-free (SPF) mice were compared at age 11 to 12 weeks (n = 6 per group). In this study, the number of neutrophils and expression of intercellular adhesion molecule (ICAM)-1, fibroblast growth factor receptor (FGFR)-1, matrix metalloproteinase (MMP)-1, and MMP-8 within the JE and the PCT are evaluated. The collagen density was also determined in PCT stained with picrosirius red (PSR). PSR staining combined with or without polarized light microscopy has been used to assess the organization and maturation of collagen matrix.
  
  
  RESULTS
  In the present findings, the area of JE in SPF mice was significantly greater than that in GF mice (P <0.05). In addition, the JE and PCT in SPF mice showed greater migration of neutrophils and higher expression of ICAM-1, FGFR-1, MMP-1, and MMP-8 than those in GF mice (P <0.05). Furthermore, the density of collagen in PCT in SPF mice was lower compared to GF mice (P <0.05).
  
  
  CONCLUSIONS
  These results indicate that commensal bacteria induced a low-grade inflammatory state in JE and that such conditions may contribute to degradation of collagen in PCT in mice.
authors: Department of Preventive Dentistry and Dental Public Health, School of Dentistry, Aichi Gakuin University, Nagoya, Aichi, Japan.|Department of Periodontics, School of Dentistry, University of Washington, Seattle, WA.|Department of Preventive Dentistry and Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Okayama, Japan.
authors: Koichiro
authors: K
authors: Irie
authors: Department of Preventive Dentistry and Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Okayama, Japan.
authors: Takaaki
authors: T
authors: Tomofuji
authors: Department of Preventive Dentistry and Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Okayama, Japan.
authors: Daisuke
authors: D
authors: Ekuni
authors: Department of Preventive Dentistry and Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Okayama, Japan.
authors: Manabu
authors: M
authors: Morita
authors: Department of Preventive Dentistry and Dental Public Health, School of Dentistry, Aichi Gakuin University, Nagoya, Aichi, Japan.
authors: Yoshihiro
authors: Y
authors: Shimazaki
authors: Department of Periodontics, School of Dentistry, University of Washington, Seattle, WA.
authors: Richard P
authors: RP
authors: Darveau
mesh_terms: D000818:Animals; D001391:Azo Compounds; D001419:Bacteria / Q000276:immunology*; D002465:Cell Movement / Q000276:immunology; D003094:Collagen / Q000032:analysis / Q000648:ultrastructure; D004396:Coloring Agents; D003238:Connective Tissue / Q000276:immunology / Q000382:microbiology; D004846:Epithelial Attachment / Q000276:immunology / Q000382:microbiology*; D005856:Germ-Free Life; D007113:Immunity, Innate / Q000276:immunology; D018799:Intercellular Adhesion Molecule-1 / Q000032:analysis; D053509:Matrix Metalloproteinase 13 / Q000032:analysis; D020784:Matrix Metalloproteinase 8 / Q000032:analysis; D051379:Mice; D008859:Microscopy, Polarization / Q000379:methods; D009055:Mouth / Q000382:microbiology*; D009504:Neutrophils / Q000276:immunology; D010519:Periodontium / Q000276:immunology / Q000382:microbiology*; D051496:Receptor, Fibroblast Growth Factor, Type 1 / Q000032:analysis; D013047:Specific Pathogen-Free Organisms; D013559:Symbiosis / Q000276:immunology*
chemical_list: D001391:Azo Compounds; D004396:Coloring Agents; D018799:Intercellular Adhesion Molecule-1; C009798:C.I. direct red 80; D003094:Collagen; C496349:Fgfr1 protein, mouse; D051496:Receptor, Fibroblast Growth Factor, Type 1; D053509:Matrix Metalloproteinase 13; C507081:Mmp13 protein, mouse; C576328:MMP8 protein, mouse; D020784:Matrix Metalloproteinase 8
keywords: Connective tissue; immunity, innate; inflammation; periodontitis