title: Histochemical localization of Dickkopf-1 in induced rat periapical lesions.
abstract: BACKGROUND
  The purpose of this study was to evaluate the expression of Dickkopf-1 (DKK-1), a secreted antagonist of the Wnt (wingless)/beta-catenin signaling pathway, during the development of periapical lesions in rats.
  
  
  METHODS
  Periapical lesions were induced in Wistar rats by occlusal exposure of the pulp of their mandibular first molars. The animals were sacrificed randomly at 0, 7, 14, 21, and 28 day after pulpal exposure. Jaws containing the first molar were obtained and routinely prepared for histologic, immunohistochemical, and enzyme histochemical double immunofluorescence analyses. Data were analyzed using 1-way analysis of variance and Pearson correlation test.
  
  
  RESULTS
  The expansion of the area of periapical lesions was visible from days 7-21 and slowed down thereafter. A few DKK-1- and receptor activator of nuclear factor kappa B ligand (RANKL)-positive cells and osteoclasts were observed on day 7. All positive samples peaked in number on day 14. The expression levels of DKK-1 and RANKL and the number of osteoclasts decreased on days 21 and 28. DKK-1 expression was positively correlated with RANKL expression and osteoclast number from days 7-28.
  
  
  CONCLUSIONS
  DKK-1 expression was up-regulated during periapical lesion development. DKK-1 may be associated with the inflammatory response and bone resorption in periapical lesions.
authors.affiliation: Department of Operative Dentistry and Endodontics, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.affiliation: State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education School and Hospital of Stomatology, Wuhan University, Wuhan, China.
authors.forename: Shengfu
authors.initials: S
authors.lastname: Huang
authors.affiliation: Department of Operative Dentistry and Endodontics, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education School and Hospital of Stomatology, Wuhan University, Wuhan, China. Electronic address: phs301@vip.163.com.
authors.forename: Bin
authors.initials: B
authors.lastname: Peng
mesh_terms: D000135:Acid Phosphatase / Q000032:analysis; D016301:Alveolar Bone Loss / Q000378:metabolism / Q000473:pathology; D000818:Animals; D015415:Biomarkers / Q000032:analysis; D002452:Cell Count; D003789:Dental Pulp Exposure / Q000150:complications; D007091:Image Processing, Computer-Assisted / Q000379:methods; D036341:Intercellular Signaling Peptides and Proteins / Q000032:analysis*; D007527:Isoenzymes / Q000032:analysis; D008297:Male; D010010:Osteoclasts / Q000473:pathology; D010485:Periapical Periodontitis / Q000209:etiology / Q000378:metabolism*; D010486:Periapical Tissue / Q000737:chemistry / Q000473:pathology; D053245:RANK Ligand / Q000032:analysis; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D000071681:Tartrate-Resistant Acid Phosphatase; D013997:Time Factors
chemical_list: D015415:Biomarkers; C531384:Dkk1 protein, rat; D036341:Intercellular Signaling Peptides and Proteins; D007527:Isoenzymes; D053245:RANK Ligand; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase
keywords: Dickkopf-1; osteoclast; periapical lesion; receptor activator of nuclear factor kappa B ligand