Bouvet-Gerbettaz Sébastien, Merigo Elisabetta, Rocca Jean-Paul, Carle Georges F, Rochet Nathalie
Laboratory of Genetics, Physiopathology and Bone Tissue Engineering (GéPITOs), University of Nice-Sophia Antipolis, Centre National de la Recherche Scientifique (CNRS), UFR of Medicine, 28 Valombrose Avenue, 06107 Nice, France.
Lasers Surg Med. 2009 Apr;41(4):291-7. doi: 10.1002/lsm.20759.
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.
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.
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.
低强度激光疗法（LLLT）已被认为可促进骨组织愈合。参与此效应的细胞和分子机制仍不清楚，但有人提出骨细胞增殖和分化发生了改变。本研究的目的是在体外研究LLLT对骨细胞增殖、成骨细胞和破骨细胞分化的影响，这些过程均参与骨重塑和再生。
研究设计/材料与方法：培养含有成骨细胞和破骨细胞祖细胞的小鼠骨髓细胞，并在不存在或存在LLLT的情况下诱导其分化。使用功率计确定激光照射参数，采用连续模式的808nm红外波长激光，能量密度为4J/cm²，每周照射三次。在不同时间对培养物进行特异性染色和显微镜分析后评估细胞增殖和分化情况，同时在核酸提取后通过定量RT-PCR分析一组成骨细胞和破骨细胞标志物。
使用功率计显示，激光设备光纤发射的功率与显示功率相比明显降低。这使得可以将LLLT参数调整到最终能量密度暴露为4J/cm²。在这些条件下，发现对照组和LLLT条件下骨髓间充质干细胞的增殖以及相应祖细胞的破骨细胞或成骨细胞分化情况相似。
采用本实验方案，我们得出结论，808nm波长的红外LLLT不会改变小鼠骨祖细胞的增殖和分化。此外，我们的结果证实了使用功率计来确定LLLT方案参数的必要性。
