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Effects of low‐level laser therapy on proliferation and differentiation of murine bone marrow cells into osteoblasts and osteoclasts
Author(s) -
BouvetGerbettaz Sébastien,
Merigo Elisabetta,
Rocca JeanPaul,
Carle Georges F.,
Rochet Nathalie
Publication year - 2009
Publication title -
lasers in surgery and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 112
eISSN - 1096-9101
pISSN - 0196-8092
DOI - 10.1002/lsm.20759
Subject(s) - osteoclast , osteoblast , progenitor cell , low level laser therapy , mesenchymal stem cell , cell growth , bone marrow , bone healing , chemistry , alkaline phosphatase , cellular differentiation , viability assay , stem cell , microbiology and biotechnology , cell , in vitro , pathology , medicine , laser , laser therapy , biology , anatomy , biochemistry , physics , gene , optics , enzyme
Background and Objective Low‐Level Laser Therapy (LLLT) has been suggested to improve bone tissue healing. The cellular and molecular mechanisms involved in this effect are still unclear but bone cell proliferation and differentiation alteration have been proposed. The aim of the present study was to investigate, in vitro, the effect of LLLT on bone cell proliferation, osteoblastic and osteoclastic differentiation, both involved in bone remodeling and regeneration. Study Design/Materials and Methods Murine bone marrow cells, which contain both osteoblast and osteoclast progenitors, were cultured and induced to differentiate in the absence or in the presence of LLLT. Laser exposition parameters were determined using a powermeter and consisted in an 808 nm infrared wavelength laser light in continuous mode, with an energy density of 4 J/cm 2 administered three times a week. Cell proliferation and differentiation were assessed after specific staining and microscopic analysis of the cultures after various times, as well as by quantitative RT‐PCR analysis of a panel of osteoblast and osteoclast markers after nucleic acid extraction. Results The use of a powermeter revealed that the power emitted by the optical fiber of the laser device was markedly reduced compared to the displayed power. This allowed to adjust the LLLT parameters to a final energy density exposure of 4 J/cm 2 . In these conditions, proliferation of bone marrow mesenchymal stem cells as well as osteoclast or osteoblast differentiation of the corresponding progenitors were found similar in control and LLLT conditions. Conclusion Using the present experimental protocol, we concluded that an 808 nm wavelength infrared LLLT does not alter murine bone progenitor cell proliferation and differentiation. Moreover our results confirm the necessary use of a powermeter to fix LLLT protocol parameters. Lasers Surg. Med. 41:291–297, 2009. © 2009 Wiley‐Liss, Inc.