title: Stimulatory effects of hydroxyl radical generation by Ga-Al-As laser irradiation on mineralization ability of human dental pulp cells.
abstract: The present study was conducted to investigate the effects of Ga-Al-As laser irradiation on the mineralization ability of human dental pulp (HDP) cells. HDP cells in vitro were irradiated once with a Ga-AL-As laser at 0.5 W for 500 s and at 1.0 W for 500 s in order to investigate free radicals as one mechanism for transmission of laser photochemical energy to cells. Production of the hydroxyl radical (*OH) was measured using the ESR spin-trapping method and was found to be increased by laser irradiation. The DMPO-OH was not detected in the presence of dimethyl sulfoxide (DMSO), a *OH scavenger. The formation of calcification nodule was also investigated by von Kossa staining. The number of calcified nodules was increased by 1.0 W-laser irradiation. Alkaline phosphatase (ALP) activity was higher in the 1.0 W-laser irradiation group. Expression of mRNAs for heat shock protein 27, bone morphogenetic proteins (BMPs) and ALP were greater in the 1.0 W-laser irradiation group. Expression of BMPs in the conditioned medium was also higher in the 1.0 W-laser irradiation group. In particular, DMSO decreased the number of calcified nodule produced by 1.0 W-laser irradiation. These results supposed that the mineralization of HDP cells is stimulated by laser irradiation, and that *OH generated by laser irradiation is a trigger for promotion of HDP cell mineralization.
authors.affiliation: Department of Endodontics, Nihon University School of Dentistry at Matsudo, Chiba, Japan. matsui.satoshi@nihon-u.ac.jp
authors.forename: Satoshi
authors.initials: S
authors.lastname: Matsui
authors.forename: Yasuhisa
authors.initials: Y
authors.lastname: Tsujimoto
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Matsushima
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000535:Aluminum; D001149:Arsenates; D055396:Bone Morphogenetic Protein 2; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D002478:Cells, Cultured; D003782:Dental Pulp / Q000378:metabolism / Q000503:physiopathology / Q000528:radiation effects*; D003784:Dental Pulp Calcification / Q000209:etiology / Q000378:metabolism* / Q000503:physiopathology; D004307:Dose-Response Relationship, Radiation; D004578:Electron Spin Resonance Spectroscopy; D005708:Gallium; D055551:HSP27 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D017665:Hydroxyl Radical / Q000378:metabolism*; D007834:Lasers / Q000009:adverse effects; D028022:Low-Level Light Therapy / Q000009:adverse effects; D018832:Molecular Chaperones; D009363:Neoplasm Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019097:Spin Trapping; D013997:Time Factors; D014074:Tooth Calcification / Q000528:radiation effects*; D016212:Transforming Growth Factor beta / Q000378:metabolism
chemical_list: D001149:Arsenates; C525718:BMP2 protein, human; C525809:BMP4 protein, human; D055396:Bone Morphogenetic Protein 2; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D055551:HSP27 Heat-Shock Proteins; C057725:HSPB1 protein, human; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D017665:Hydroxyl Radical; D005708:Gallium; D000535:Aluminum; D000469:Alkaline Phosphatase; C025657:arsenic acid