title: Immunolocalization of matrix metalloproteinases-2 and -9 during apical periodontitis development.
abstract: OBJECTIVE
  The objective of this study was to determine the expression of matrix metalloproteinase-2 (MMP-2) and -9 (MMP-9) during apical periodontitis development.
  
  
  METHODS
  Using an experimental design of induced periapical lesions in rats and immunohistochemistry assay as investigative tool, the MMP-2 and MMP-9 expression and distribution were evaluated at 3, 7, 14, 21, 30, 60 and 90 days after coronary access and pulp exposure of the first left mandibular molar to the oral environment. Two blind observers scored the immunoreactivity. A semi-quantitative analysis was performed.
  
  
  RESULTS
  Except at day 3, MMP-2 and MMP-9 immunostaining was observed in all experimental periods. The MMP-2 (p=0.004) and MMP-9 (p=0.005) immunostaining was higher in the period between 7 and 21 days. They were mainly observed in cells surrounding the apical foramen and adjacent periapical areas. Cells into the hypercementosis areas were strongly stained while both osteoblasts and osteoclasts presented discrete staining along of this study. No staining was observed on epithelial walls. At 30, 60 and 90 days, the subjacent connective tissue presented intense MMP-2 and MMP-9 immunostaining in mononuclear cells (suggestive of fibroblasts, macrophages, infiltrating neutrophils and lymphocytes).
  
  
  CONCLUSIONS
  The results observed in this study suggest that MMP-2 and MMP-9 play a critical role in the development of inflammatory periapical lesions, probably involved in the extracellular matrix (ECM) degradation during the initial phase of the lesion development.
authors.affiliation: Laboratory of Biochemistry, Department of Biological Sciences, University of Sao Paulo, Bauru-SP, Brazil.
authors.forename: Mauro V
authors.initials: MV
authors.lastname: Corotti
authors.forename: Willian F
authors.initials: WF
authors.lastname: Zambuzzi
authors.forename: Katiúcia B S
authors.initials: KB
authors.lastname: Paiva
authors.forename: Renato
authors.initials: R
authors.lastname: Menezes
authors.forename: Lidiane C
authors.initials: LC
authors.lastname: Pinto
authors.forename: Vanessa S
authors.initials: VS
authors.lastname: Lara
authors.forename: José M
authors.initials: JM
authors.lastname: Granjeiro
mesh_terms: D000818:Animals; D003238:Connective Tissue / Q000201:enzymology / Q000473:pathology; D003789:Dental Pulp Exposure / Q000150:complications; D004195:Disease Models, Animal; D005109:Extracellular Matrix / Q000201:enzymology / Q000473:pathology; D005347:Fibroblasts / Q000201:enzymology / Q000473:pathology; D006936:Hypercementosis / Q000201:enzymology / Q000473:pathology; D007150:Immunohistochemistry; D008214:Lymphocytes / Q000201:enzymology / Q000473:pathology; D008264:Macrophages / Q000201:enzymology / Q000473:pathology; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000032:analysis*; D020780:Matrix Metalloproteinase 9 / Q000032:analysis*; D009504:Neutrophils / Q000201:enzymology / Q000473:pathology; D010006:Osteoblasts / Q000201:enzymology / Q000473:pathology; D010010:Osteoclasts / Q000201:enzymology / Q000473:pathology; D010485:Periapical Periodontitis / Q000201:enzymology* / Q000209:etiology / Q000473:pathology; D010486:Periapical Tissue / Q000201:enzymology / Q000473:pathology; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D019227:Tooth Apex / Q000201:enzymology / Q000473:pathology
chemical_list: D020778:Matrix Metalloproteinase 2; C522363:Mmp2 protein, rat; D020780:Matrix Metalloproteinase 9