title: Different doses of low-level laser irradiation modulate the in vitro response of osteoblast-like cells.
abstract: Because osteoblasts play a key role in bone remodeling and the influence of low-level laser therapy on this process is not clear, Saos-2 human osteoblast-like cells were irradiated by a gallium-aluminum-arsenide diode laser (915 nm) for 10, 48, 96, 193, and 482 s using doses 1, 5, 10, 20, and 50 J/cm2, respectively. A control group was not irradiated. Morphology, viability, and cytotoxicity analyses were carried out after 1 hr, 1 day, and 3 days. Deoxyribose nucleic acid (DNA) content and release of vascular endothelial growth factor (VEGF), receptor activator of nuclear factor kappa B ligand (RANKL), and osteoprotegerin (OPG) were evaluated. Viability was modulated by laser irradiation in a dose-dependent manner, with 10 J/cm2 inducing a biostimulatory response and 20 to 50 J/cm2 determining a bioinhibitory and cytotoxic effect. Accordingly, DNA content was generally increased for the 10 J/cm2 dose and decreased for the 50 J/cm2 dose. A rapid and transitory trend toward increased RANKL/OPG ratio and a tendency toward a delayed increase in VEGF release for doses of 1 to 10 J/cm2 was found. Further investigations using the biostimulatory dose of 10 J/cm2 emerged from this study are needed to establish the ideal treatment regimens in the laboratory as well as in clinical practice.
authors.affiliation: University of Bologna, Department of Biomedical and Neuromotor Sciences, Unit of Periodontology and Orthodontics, via San Vitale 59, 40125 Bologna, Italy.
authors.forename: Serena
authors.initials: S
authors.lastname: Incerti Parenti
authors.affiliation: University of Bologna, Department of Biomedical and Neuromotor Sciences, Unit of Periodontology and Orthodontics, via San Vitale 59, 40125 Bologna, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Checchi
authors.affiliation: Rizzoli Orthopaedic Institute, Laboratory of Preclinical and Surgical Studies, via di Barbiano 1/10, 40136 Bologna, ItalycRizzoli Orthopaedic Institute, Laboratory of Biocompatibility, Technological Innovations and Advanced Therapies, Research, Innovation.
authors.forename: Milena
authors.initials: M
authors.lastname: Fini
authors.affiliation: Rizzoli Orthopaedic Institute, Laboratory of Preclinical and Surgical Studies, via di Barbiano 1/10, 40136 Bologna, ItalycRizzoli Orthopaedic Institute, Laboratory of Biocompatibility, Technological Innovations and Advanced Therapies, Research, Innovation.
authors.forename: Matilde
authors.initials: M
authors.lastname: Tschon
mesh_terms: D002460:Cell Line; D048430:Cell Shape / Q000528:radiation effects; D002470:Cell Survival / Q000528:radiation effects*; D004247:DNA / Q000032:analysis; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000032:analysis / Q000378:metabolism; D054023:Lasers, Semiconductor; D008856:Microscopy, Fluorescence; D010006:Osteoblasts / Q000528:radiation effects*
chemical_list: D004247:DNA; D007770:L-Lactate Dehydrogenase