title: Low intensity lasers differently induce primary human osteoblast proliferation and differentiation.
abstract: Among various compounds used in research and clinic for degenerative bone diseases, low level laser therapy (LLLT), comprising low level lasers (LLL) and light emitting diodes (LEDs), has been investigated regarding its effects on bone metabolism. They have specific wavelengths but in general act as a cellular biomodulator, and as a therapeutic agent, rebalancing and normalizing their activity. However, they are not standardized yet, since their parameters of use are relevant for the effects and mechanisms of action. Therefore, the aim of this study was to compare the influence of two spectrums of LLL and LED phototherapy, at the same energy densities (10 and 50J/cm(2)), on human osteoblasts proliferation and differentiation. The involvement of ERK signaling on proliferation was also investigated by evaluating its activation during proliferation under different phototherapies by western blotting and CFSE-based osteoblast proliferation was measured in a presence or absence of the ERK-specific inhibitor. Osteogenic differentiation was evaluated through in vitro mineralization and gene expression of type I collagen (COL1A1) and osteonectin (SPARC) by Real Time- PCR. Increases in viable cells and proliferation were obtained after irradiation, regardless of LLLT type. However, only red at 10J/cm(2) and infrared at both doses, but not LED, induced ERK1/2 activation. In the presence of ERK inhibitor, the LLL-induced proliferation was prevented. In addition, while COL1A1 gene expression was upregulated by red laser, SPARC does so by infrared stimulation. However, LED, at both doses, increased both COL1A1 and SPARC expression. All LLLT increased mineralization, dependent on the dose and time. Thus, LLL and LED differently modulated the metabolism of human osteoblasts, increasing proliferation by mechanism dependent or not of ERK signaling activation and osteogenic differentiation markers.
authors: Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
authors: Flávia A
authors: FA
authors: Oliveira
authors: Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
authors: Adriana A
authors: AA
authors: Matos
authors: Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
authors: Mariana R
authors: MR
authors: Santesso
authors: Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
authors: Cintia K
authors: CK
authors: Tokuhara
authors: Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
authors: Aline L
authors: AL
authors: Leite
authors: Departamento de Física e Ciência dos Materiais, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil.
authors: Vanderley S
authors: VS
authors: Bagnato
authors: Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
authors: Maria A A M
authors: MA
authors: Machado
authors: Pró-Reitoria de Pesquisa e Pós-Graduação, Universidade do Sagrado Coração, Bauru, SP, Brazil.
authors: Camila
authors: C
authors: Peres-Buzalaf
authors: Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil. Electronic address: rodrigocardoso@usp.br.
authors: Rodrigo C
authors: RC
authors: Oliveira
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D002113:Calcification, Physiologic / Q000528:radiation effects; D002454:Cell Differentiation / Q000528:radiation effects*; D049109:Cell Proliferation / Q000528:radiation effects; D002470:Cell Survival / Q000528:radiation effects; D024042:Collagen Type I / Q000378:metabolism; D006801:Humans; D028022:Low-Level Light Therapy; D020935:MAP Kinase Signaling System / Q000528:radiation effects; D010006:Osteoblasts / Q000166:cytology* / Q000378:metabolism / Q000528:radiation effects*; D010012:Osteogenesis / Q000528:radiation effects; D015676:Osteonectin / Q000378:metabolism
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D015676:Osteonectin
keywords: ERK; Human osteoblasts; LED; LLL; LLLT; Phototherapy