title: Initial effects of low-level laser therapy on growth and differentiation of human osteoblast-like cells.
abstract: Low-level laser therapy is a clinically well established tool for enhancement of wound healing. In vitro studies have also shown that low level laser therapy has a biostimulatory effect on cells of different origin. The aim of this in vitro study was to investigate the initial effect of low-level laser therapy on growth and differentiation of human osteoblast-like cells. SaOS-2 cells were irradiated with laser doses of 1 J/cm2 and 2 J/cm2 using a diode laser with 670 nm wave length and an output power of 400 mW. Untreated cells were used as controls. At 24 h, 48 h and 72 h post irradiation, cells were collected and assayed for viability of attached cells and alkaline phosphatase specific activity. In addition, mRNA expression levels of osteopontin and collagen type I were assessed using semi-quantitative RT-PCR. Over the observation period, cell viability, alkaline phosphatase activity and the expression of osteopontin and collagen type I mRNA were slightly enhanced in cells irradiated with 1 J/cm2 compared with untreated control cells. Increasing the laser dose to 2 J/cm2 reduced cell viability during the first 48 h and resulted in persistently lower alkaline phosphatase activity compared with the other two groups. The expression of osteopontin and collagen type I mRNA slightly decreased with time in untreated controls and cells irradiated with 1 J/cm2, but their expression was increased by treatment with 2 J/cm2 after 72 h. These results indicate that low-level laser therapy has a biostimulatory effect on human osteoblast-like cells during the first 72 h after irradiation. Further studies are needed to determine the potential of low-level laser therapy as new treatment concept in bone regeneration.
authors.affiliation: Department of Cranio-Maxillofacial and Oral Surgery, Medical University of Vienna, Austria.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Stein
authors.forename: Jadranka
authors.initials: J
authors.lastname: Koehn
authors.forename: Walter
authors.initials: W
authors.lastname: Sutter
authors.forename: Gabriele
authors.initials: G
authors.lastname: Wendtlandt
authors.forename: Felix
authors.initials: F
authors.lastname: Wanschitz
authors.forename: Dietmar
authors.initials: D
authors.lastname: Thurnher
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Baghestanian
authors.forename: Dritan
authors.initials: D
authors.lastname: Turhani
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D002454:Cell Differentiation / Q000528:radiation effects*; D002455:Cell Division / Q000528:radiation effects*; D002460:Cell Line; D002470:Cell Survival / Q000528:radiation effects; D024042:Collagen Type I / Q000235:genetics; D015870:Gene Expression / Q000528:radiation effects; D006801:Humans; D066298:In Vitro Techniques; D054023:Lasers, Semiconductor; D028022:Low-Level Light Therapy; D010006:Osteoblasts / Q000528:radiation effects*; D053495:Osteopontin / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics*; D011879:Radiotherapy Dosage; D054631:Receptor-Like Protein Tyrosine Phosphatases, Class 3; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D024042:Collagen Type I; D012333:RNA, Messenger; D053495:Osteopontin; D000469:Alkaline Phosphatase; D054631:Receptor-Like Protein Tyrosine Phosphatases, Class 3