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Low pulse energy Nd:YAG laser irradiation exerts a biostimulative effect on different cells of the oral microenvironment: “An in vitro study”
Author(s) -
Chellini Flaminia,
Sassoli Chiara,
Nosi Daniele,
Deledda Cristiana,
Tonelli Paolo,
ZecchiOrlandini Sandra,
Formigli Lucia,
Giannelli Marco
Publication year - 2010
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.20861
Subject(s) - osteopontin , viability assay , irradiation , runx2 , intracellular , cell growth , laser , chemistry , biophysics , endothelial stem cell , cell , osteoblast , in vitro , microbiology and biotechnology , materials science , medicine , biochemistry , biology , physics , nuclear physics , optics
Background and Objectives Dental lasers represent a promising therapeutic tool in the treatment of periodontal and peri‐implant diseases. However, their clinical application remains still limited. Here, we investigated the potential biostimulatory effect of low pulse energy neodymium:yttrium–aluminum–garnet (Nd:YAG) laser irradiation on different cells representative of the oral microenvironment and elucidated the underlying molecular mechanisms. Materials and Methods Saos‐2 osteoblasts, H‐end endothelial cells, and NIH/3T3 fibroblasts pre‐treated or not with photosensitizing dye methylene blue (MB), were irradiated with low pulse energy (20 mJ) and high repetition rate (50–70 Hz) Nd:YAG laser, and evaluated for cell viability and proliferation as well as for the expression of specific differentiation markers by confocal immunofluorescence and real‐time RT‐PCR. Changes in intracellular Ca 2+ levels after laser exposure were also evaluated in living osteoblasts. Results Nd:YAG laser irradiation did not affect cell viability in all the tested cell types, even when combined with pre‐treatment with MB, and efficiently stimulated cell growth in the non‐sensitized osteoblasts. Moreover, a significant induction in the expression of osteopontin, ALP, and Runx2 in osteoblasts, type I collagen in fibroblasts, and vinculin in endothelial cells could be observed in the irradiated cells. Pre‐treatment with MB negatively affected cell differentiation in the unstimulated and laser‐stimulated cells. Notably, laser irradiation also caused an increase in the intracellular Ca 2+ in osteoblasts through the activation of TRPC1 ion channels. Moreover, the pharmacologic or genetic inhibition of these channels strongly attenuated laser‐induced osteopontin expression, suggesting a role for the laser‐mediated Ca 2+ influx in regulating osteoblast differentiation. Conclusion Low pulse energy and high repetition rate Nd:YAG laser irradiation may exert a biostimulative effect on different cells representative of the oral microenvironment, particularly osteoblasts. Pre‐treatment with MB prior to irradiation hampers this effect and limits the potential clinical application of photosensitizing dyes in dental practice. Lasers Surg. Med. 42:527–539, 2010. © 2010 Wiley–Liss, Inc.