title: Periodontal healing with a preameloblast-conditioned medium in dogs.
abstract: OBJECTIVE
  The predictability of conventional periodontal treatments for damaged periodontal tissue is limited, particularly on the regeneration of new cementum. As signaling molecules, a range of growth factors has been used to promote periodontal regeneration on periodontal ligament (PDL) and cementum defects. A preameloblast-conditioned medium (PA-CM) was prepared from cultured murine apical bud cells, which can differentiate into ameloblasts. We examined the effect of PA-CM on PDL cells and cementoblasts in vitro and evaluated histologically the effects of PA-CM on the regeneration of experimentally induced periodontal defects in vivo.
  
  
  METHODS
  In vitro, the effects of PA-CM on the migration of human PDL cells were examined using a scratch wound healing assay and a transwell assay. The differentiation and mineralization potential of PA-CM-treated human PDL cells and murine cementoblastic OCCM-30 cells was examined by real-time polymerase chain reaction and Alizarin red-S staining. In vivo, six mongrel dogs (12-16 kg; 6-8 mo old) were used. Twenty-four roots were replanted with either, (i) only periodontal defects (n = 12; control group), or (ii) periodontal defects and PA-CM treatment (n = 12; experimental group). In the experimental group, the PDL and cementum between notches was removed using a Gracey curette and soaked in 0.08 mL water containing 80 μg of a PA-CM for 2 min. The dogs were killed at 4 and 8 wk post-surgery.
  
  
  RESULTS
  The in vitro results showed that PA-CM stimulated the migration of PDL cells and promoted the differentiation and mineralization of PDL cells and cementoblasts. Real-time polymerase chain reaction analysis revealed stronger expression of Runx2, Osx, OC, Bsp and Cap mRNAs in the PA-CM-treated PDL cells and cementoblasts than those in the control cells. In vivo, newly formed PDL-like tissue and cementum-like tissue were observed partially between the root surfaces and newly formed bone in the experimental group. The regenerated PDL-like tissue in the experimental group was significantly higher than that in the control group at 8 wk (p < 0.05). The replacement resorption on the experimental group was significantly lower than that in the control group at 8 wk (p < 0.05). In addition, the amount of newly formed cementum-like tissue in the experimental group was significantly higher than that in the control group at 4 and 8 wk (p < 0.05).
  
  
  CONCLUSIONS
  These results suggest that PA-CM has the potential to regenerate periodontal tissues in PDL and cementum defects.
authors.affiliation: Department of Periodontology, School of Dentistry, Chosun University, Gwangju, South Korea.
authors.forename: S-J
authors.identifier: http://orcid.org/0000-0001-8818-549X
authors.initials: SJ
authors.lastname: Yu
authors.affiliation: Department of Oral Histology-Developmental Biology and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, South Korea.
authors.forename: D-S
authors.initials: DS
authors.lastname: Lee
authors.affiliation: Department of Periodontology, School of Dentistry, Chosun University, Gwangju, South Korea.
authors.forename: B-O
authors.initials: BO
authors.lastname: Kim
authors.affiliation: Department of Periodontology, Research Institute for Periodontal Regeneration, College of Dentistry, Yonsei University, Seoul, South Korea.
authors.forename: S-H
authors.initials: SH
authors.lastname: Choi
authors.affiliation: Department of Oral Histology-Developmental Biology and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, South Korea.
authors.forename: J-C
authors.initials: JC
authors.lastname: Park
mesh_terms: D000293:Adolescent; D000818:Animals; D002113:Calcification, Physiologic / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D054443:Cell Migration Assays; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D025021:Cementogenesis / Q000187:drug effects; D017077:Culture Media, Conditioned; D003739:Dental Cementum / Q000187:drug effects* / Q000293:injuries; D004285:Dogs; D006801:Humans; D008810:Mice, Inbred C57BL; D008964:Molar, Third; D010513:Periodontal Ligament / Q000187:drug effects*; D010519:Periodontium / Q000187:drug effects / Q000293:injuries; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D014092:Tooth Root / Q000187:drug effects / Q000293:injuries / Q000473:pathology; D014945:Wound Healing / Q000187:drug effects*; D055815:Young Adult
chemical_list: D017077:Culture Media, Conditioned; D012333:RNA, Messenger
keywords: cementoblast; periodontal healing; regeneration; replantation