title: Cementoblast response to low- and high-intensity ultrasound.
abstract: OBJECTIVE
  It has been shown that ultrasound stimulation accelerates repair of orthodontically induced root resorption. However, the mechanism of such adaptive change is still unclear. The purpose of this study was to evaluate pulsed ultrasound on the differentiation-potential and cementoblast-mediated osteoclastogenesis using a cementoblastic cell line.
  
  
  METHODS
  Cultured cementoblasts (murine cementoblastic cell line, OCCM-30) were subjected to ultrasound exposure (frequency = 1 MHz; pulsed 1:4; spatial average temporal average intensities=30 or 150 mW/cm(2)) or sham exposure for 15 min per day. Expression levels of alkaline phosphatase (ALP), type I collagen (COL-I), osteoprotegerin (OPG) and receptor activator of nuclear factor small ka, CyrillicB ligand (RANKL) mRNAs were analysed by a real-time PCR analysis. Furthermore, ALP activity, collagen synthesis, and protein levels of OPG and RANKL were examined after 6-day ultrasound exposure.
  
  
  RESULTS
  Real-time PCR analysis indicated that, irrespective of the intensity, single ultrasound exposure increased the expression of transcripts for COL-I and ALP after 24h; the expression of OPG and RANKL also increased after 1 and 4h, respectively. Cultured cementoblasts receiving ultrasound stimulation for 6 days showed a significant (p<0.05 or 0.01) increase in cell number and collagen synthesis. ALP activity and OPG synthesis were also significantly (p<0.05) upregulated by ultrasound stimulation with 150 mW/cm(2).
  
  
  CONCLUSIONS
  These results demonstrated that ultrasound stimulation especially with 150 mW/cm(2) might be a better candidate as a medical remedy to protect against root resorption and/or accelerate its repair.
authors.affiliation: Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Graduate School of Biomedical Sciences, 1-2-3 Kasumi, Minami-Ku, Hiroshima 734-8553, Japan.
authors.forename: Diego Araujo
authors.initials: DA
authors.lastname: Dalla-Bona
authors.forename: Eiji
authors.initials: E
authors.lastname: Tanaka
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Inubushi
authors.forename: Hiroko
authors.initials: H
authors.lastname: Oka
authors.forename: Atsumi
authors.initials: A
authors.lastname: Ohta
authors.forename: Haruhisa
authors.initials: H
authors.lastname: Okada
authors.forename: Mutsumi
authors.initials: M
authors.lastname: Miyauchi
authors.forename: Takashi
authors.initials: T
authors.lastname: Takata
authors.forename: Kazuo
authors.initials: K
authors.lastname: Tanne
mesh_terms: D000469:Alkaline Phosphatase / Q000096:biosynthesis / Q000235:genetics; D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D049109:Cell Proliferation; D025021:Cementogenesis / Q000502:physiology; D024042:Collagen Type I / Q000096:biosynthesis / Q000235:genetics; D003739:Dental Cementum / Q000166:cytology* / Q000378:metabolism; D005786:Gene Expression Regulation; D051379:Mice; D053244:Osteoprotegerin / Q000096:biosynthesis / Q000235:genetics; D053245:RANK Ligand / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D014464:Ultrasonic Therapy / Q000379:methods*
chemical_list: D024042:Collagen Type I; D053244:Osteoprotegerin; D053245:RANK Ligand; D012333:RNA, Messenger; D000469:Alkaline Phosphatase