title: Initial transient accumulation of M2 macrophage-associated molecule-expressing cells after pulpotomy with mineral trioxide aggregate in rat molars.
abstract: BACKGROUND
  M2 (alternatively activated) macrophages are known to participate in wound healing and tissue repair. This study aimed to analyze the temporospatial changes in the distribution and density of M2 macrophage-associated molecule-expressing cells after pulpotomy with mineral trioxide aggregate (MTA) in rat molars to ascertain the role played by M2 macrophages in the healing of MTA-capped pulp tissue.
  
  
  METHODS
  The maxillary first molars of 8-week-old Wistar rats were pulpotomized and capped with MTA. After 1-14 days, the teeth were examined after hematoxylin-eosin staining or immunoperoxidase staining of CD68 (a general macrophage marker) and M2 macrophage markers (CD163 and CD204). The density of positively stained cells was enumerated in the surface and inner regions (0-100 μm and 300-400 μm, respectively, from the wound surface).
  
  
  RESULTS
  MTA capping initially caused mild inflammatory changes and the formation of a degenerative layer followed by progressive new matrix formation and calcified bridging. At 1-2 days, CD68-, CD163-, and CD204-positive cells started to accumulate beneath the degenerative layer, and the density of these cells was significantly higher in the surface region than in the inner region (P < .05). From 7 days onward, the 3 types of cells displayed an almost normal distribution beneath the newly formed dentinlike matrix.
  
  
  CONCLUSIONS
  After the pulpotomy of rat molars with MTA, M2 macrophage-associated molecule-expressing cells transiently accumulated beneath the degenerative layer under the MTA. This suggests that M2 macrophages participate in the initial phases of the healing of MTA-capped pulp tissue.
authors.affiliation: Division of Cariology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Erika
authors.initials: E
authors.lastname: Takei
authors.affiliation: Division of Cariology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Shigetani
authors.affiliation: Division of Cariology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Yoshiba
authors.affiliation: Division of Cariology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Go
authors.initials: G
authors.lastname: Hinata
authors.affiliation: Division of Cariology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Nagako
authors.initials: N
authors.lastname: Yoshiba
authors.affiliation: Division of Cariology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan. Electronic address: t-okiji@dent.niigata-u.ac.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Okiji
mesh_terms: D017607:Aluminum Compounds / Q000494:pharmacology*; D000818:Animals; D015703:Antigens, CD / Q000032:analysis / Q000187:drug effects; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis / Q000187:drug effects; D017610:Calcium Compounds / Q000494:pharmacology*; D002452:Cell Count; D003809:Dentin, Secondary / Q000187:drug effects; D004338:Drug Combinations; D008262:Macrophage Activation / Q000187:drug effects*; D008264:Macrophages / Q000187:drug effects*; D009804:Odontoblasts / Q000187:drug effects; D010087:Oxides / Q000494:pharmacology*; D057872:Pulp Capping and Pulpectomy Agents / Q000494:pharmacology*; D011672:Pulpotomy / Q000379:methods*; D051381:Rats; D017208:Rats, Wistar; D011956:Receptors, Cell Surface / Q000032:analysis / Q000187:drug effects; D051117:Scavenger Receptors, Class A / Q000032:analysis / Q000187:drug effects; D017640:Silicates / Q000494:pharmacology*; D013997:Time Factors; D014945:Wound Healing / Q000187:drug effects; D000098902:CD163 Antigen; D000097382:CD68 Molecule
chemical_list: D017607:Aluminum Compounds; D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D017610:Calcium Compounds; D004338:Drug Combinations; D010087:Oxides; D057872:Pulp Capping and Pulpectomy Agents; D011956:Receptors, Cell Surface; D051117:Scavenger Receptors, Class A; D017640:Silicates; D000098902:CD163 Antigen; C539355:CD68 protein, rat; D000097382:CD68 Molecule; C086631:mineral trioxide aggregate
keywords: CD163; CD204; CD68; dental pulp; macrophage; mineral trioxide aggregate; pulpotomy; rat (Wistar)