title: Short-term in vitro effects of low frequency ultrasound on odontoblast-like cells.
abstract: In this study, the effects of low frequency ultrasound (US) were examined on odontoblasts, the primary cell responsible for dentinogenesis and dentine repair. An established odontoblast-like cell line, MDPC-23, was subjected to 30 kHz ultrasound at three different power settings. US induced a marginal level of cell death (3% to 4%) at lower amplitudes rising to 25% cell death at the highest power tested. The latter was reflected in a 30% decrease in cell attachment after 4 to 24 h of culture, while the number of adherent cells was reduced by approximately 10% to 15% in the lower power groups. Cell replication after 24 h, as measured by BrdU incorporation, showed no significant changes in the US-treated groups. Gene expression analyses demonstrated a moderate dose-dependent increase in the expression of GAPDH (glyseraldehyde-3-phosphate dehydrogenase)-normalised collagen type I, osteopontin (OPN), transforming growth factor-beta1 (TGFbeta1) and the heat shock protein (hsp) 70. The greatest change was found in the expression of the small hsp 25/27, which showed a two- to six-fold increase following US treatment. No significant effects were observed for alkaline phosphatase (ALP) and core-binding factor A1 (CBFA1/Runx2) expression levels. This is the first report describing US effects on odontoblasts. Further studies are warranted to elucidate US effects on odontoblast function and to evaluate US as a therapeutic application in dentine repair.
authors.affiliation: School of Dentistry, University of Birmingham, St. Chad's Queensway, Birmingham, UK. b.a.scheven@bham.ac.uk
authors.forename: Ben A
authors.initials: BA
authors.lastname: Scheven
authors.forename: Jane L
authors.initials: JL
authors.lastname: Millard
authors.forename: Paul R
authors.initials: PR
authors.lastname: Cooper
authors.forename: Simon C
authors.initials: SC
authors.lastname: Lea
authors.forename: A Damien
authors.initials: AD
authors.lastname: Walmsley
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Smith
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000032:analysis; D002448:Cell Adhesion / Q000502:physiology; D016923:Cell Death / Q000502:physiology; D002455:Cell Division / Q000502:physiology; D002460:Cell Line; D002470:Cell Survival / Q000502:physiology; D024042:Collagen Type I / Q000235:genetics; D015870:Gene Expression; D006360:Heat-Shock Proteins / Q000235:genetics; D051379:Mice; D009804:Odontoblasts / Q000502:physiology*; D053495:Osteopontin / Q000235:genetics; D053773:Transforming Growth Factor beta1 / Q000235:genetics; D014465:Ultrasonics
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D006360:Heat-Shock Proteins; C506896:Spp1 protein, mouse; D053773:Transforming Growth Factor beta1; D053495:Osteopontin