title: Expression of MMP-8 and MMP-13 in the development of periradicular lesions.
abstract: OBJECTIVE
  To elucidate the expressions of MMP-8 and MMP-13 in experimentally induced rat periradicular lesions by means of the reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemical staining.
  
  
  METHODS
  Thirty rats were used and periradicular lesions in mandibular first molar teeth were established following pulp exposure. The animals were sacrificed at 0 (no exposure control), 1, 2, 3, 4 and 6 weeks after pulp exposure. The right molars were used for RT-PCR analysis of MMP-8 and MMP-13. The left molars were subjected to immunohistochemical staining with both MMPs. The areas of these lesions were measured histometrically, and the numbers of both reactive cells in the periapical portion were counted per unit area. Significant differences were analysed by the Mann-Whitney U-test.
  
  
  RESULTS
  MMP-8 gene expression gradually increased from 2 to 4 weeks, but slightly decreased at 6 weeks. MMP-13 gene expression gradually increased from 1 to 3 weeks. At 4 and 6 weeks, the level of expression was as high as that at 3 weeks. Immunohistochemically, MMP-8 was first detected at 2 weeks and gradually increased until 4 weeks. MMP-13 gradually increased from 1 to 4 weeks. Both MMPs decreased at 6 weeks. The area of the periradicular lesions gradually increased from 1 to 4 weeks, showing a large increase in week 2 and 3 in particular, but then decreased in week 6. MMP-13-expressing cells were significantly greater than MMP-8-positive cells at week 1 and 2.
  
  
  CONCLUSIONS
  These findings indicate that MMP-8 and MMP-13 were related to the development of periradicular lesions. It is suggested that MMP-13 increased from an early stage during their development and that MMP-8 is involved in the progression of tissue destruction including bone resorption.
authors: Department of Endodontics, School of Dentistry, Aichi-Gakuin University, Chkusa-ku, Nagoya, Japan.
authors: H
authors: H
authors: Matsui
authors: M
authors: M
authors: Yamasaki
authors: K
authors: K
authors: Nakata
authors: K
authors: K
authors: Amano
authors: H
authors: H
authors: Nakamura
mesh_terms: D016301:Alveolar Bone Loss / Q000201:enzymology* / Q000235:genetics; D000818:Animals; D015870:Gene Expression; D008297:Male; D053509:Matrix Metalloproteinase 13 / Q000096:biosynthesis* / Q000235:genetics; D020784:Matrix Metalloproteinase 8 / Q000096:biosynthesis* / Q000235:genetics; D010485:Periapical Periodontitis / Q000201:enzymology* / Q000235:genetics; D010513:Periodontal Ligament / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D053509:Matrix Metalloproteinase 13; D020784:Matrix Metalloproteinase 8