title: Temporospatial localization of dentine matrix protein 1 following direct pulp capping with calcium hydroxide in rat molars.
abstract: OBJECTIVE
  To examine the temporospatial expression of dentine matrix protein 1 (DMP1; a noncollagenous protein involved in mineralized tissue formation), osteopontin (another noncollagenous protein detected during reparative dentinogenesis) and nestin (a marker of differentiating/differentiated odontoblasts), following direct pulp capping with calcium hydroxide in rat molars.
  
  
  METHODS
  The maxillary first molars of 8-week-old Wistar rats had their pulps exposed and capped with calcium hydroxide. The pulp-capped teeth were collected from 6 h to 14 days postoperatively and processed for immunohistochemistry for DMP1, osteopontin and nestin. Cell proliferation was monitored using 5-bromo-2'-deoxyuridine (BrdU) labelling.
  
  
  RESULTS
  The capped pulps initially exhibited superficial necrotic changes followed by the formation of new matrix and its mineralization. DMP1 immunoreactivity was observed in the matrix beneath the necrotic layer from 6 h onwards and present in the outer portion of the newly formed mineralized matrix from 7 days onwards. Osteopontin displayed a similar expression pattern, although it occupied a narrower area than DMP1 at 6 and 12 h. Nestin-immunoreactive cells appeared beneath the DMP1-immunoreactive area at 1 day, were distributed beneath the newly formed matrix at 5 days and exhibited odontoblast-like morphology by 14 days. BrdU-positive cells significantly increased at 2 and 3 days (P < 0.05) and then decreased.
  
  
  CONCLUSIONS
  The deposition of DMP1 at exposed pulp sites preceded the appearance of nestin-immunoreactive cells, active cell proliferation and new matrix formation after pulp capping with calcium hydroxide in rat molars, suggesting that DMP1 acts as a trigger of pulp repair. The colocalization of DMP1 and osteopontin suggests that these two proteins play complementary roles.
authors: Division of Cariology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors: Y
authors: Y
authors: Shigetani
authors: Division of Cariology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors: K
authors: K
authors: Yoshiba
authors: Division of Cariology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors: M
authors: M
authors: Kuratate
authors: Division of Cariology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors: E
authors: E
authors: Takei
authors: Division of Cariology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors: N
authors: N
authors: Yoshiba
authors: Division of Cariology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors: Y
authors: Y
authors: Yamanaka
authors: Division of Anatomy and Cell Biology of the Hard Tissue, Department of Tissue Regeneration and Reconstruction, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors: H
authors: H
authors: Ohshima
authors: Division of Cariology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors: T
authors: T
authors: Okiji
mesh_terms: D000818:Animals; D002126:Calcium Hydroxide; D049109:Cell Proliferation; D003785:Dental Pulp Capping; D003790:Dental Pulp Necrosis / Q000628:therapy*; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008963:Molar; D064231:Nestin / Q000378:metabolism; D053495:Osteopontin / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
chemical_list: C081635:Dmp1 protein, rat; D016326:Extracellular Matrix Proteins; D064231:Nestin; D010750:Phosphoproteins; D053495:Osteopontin; D002126:Calcium Hydroxide
keywords: calcium hydroxide; dental pulp capping; dental pulp exposure; dentine matrix protein 1; nestin; osteopontin