Low-power GaAlAs laser irradiation promotes the proliferation and osteogenic differentiation of stem cells via IGF1 and BMP2

PLoS One. 2012;7(9):e44027. doi: 10.1371/journal.pone.0044027. Epub 2012 Sep 4.

Abstract

Low-power laser irradiation (LPLI) has been found to induce various biological effects and cellular processes. Also, LPLI has been shown to promote fracture repair. Until now, it has been unclear how LPLI promotes bone formation and fracture healing. The aim of this study was to investigate the potential mechanism of LPLI-mediated enhancement of bone formation using mouse bone marrow mesenchymal stem cells (D1 cells). D1 cells were irradiated daily with a gallium-aluminum-arsenide (GaAlAs) laser at dose of 0, 1, 2, or 4 J/cm(2). The lactate dehydrogenase (LDH) assay showed no cytotoxic effects of LPLI on D1 cells, and instead, LPLI at 4 J/cm(2) significantly promoted D1 cell proliferation. LPLI also enhanced osteogenic differentiation in a dose-dependent manner and moderately increased expression of osteogenic markers. The neutralization experiments indicated that LPLI regulated insulin-like growth factor 1 (IGF1) and bone morphogenetic protein 2 (BMP2) signaling to promote cell proliferation and/or osteogenic differentiation. In conclusion, our study suggests that LPLI may induce IGF1 expression to promote both the proliferation and osteogenic differentiation of D1 cells, whereas it may induce BMP2 expression primarily to enhance osteogenic differentiation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bone Marrow Cells / cytology
  • Bone Marrow Cells / radiation effects*
  • Bone Morphogenetic Protein 2 / genetics
  • Bone Morphogenetic Protein 2 / metabolism*
  • Cell Differentiation / radiation effects
  • Cell Proliferation / radiation effects
  • Cells, Cultured
  • Gene Expression / radiation effects
  • Insulin-Like Growth Factor I / genetics
  • Insulin-Like Growth Factor I / metabolism*
  • Lasers, Semiconductor*
  • Mesenchymal Stem Cells / cytology
  • Mesenchymal Stem Cells / radiation effects*
  • Mice
  • Mice, Inbred BALB C
  • Osteogenesis / radiation effects*
  • Signal Transduction / radiation effects

Substances

  • Bmp2 protein, mouse
  • Bone Morphogenetic Protein 2
  • insulin-like growth factor-1, mouse
  • Insulin-Like Growth Factor I

Grants and funding

This study was supported by two grants from the National Science Council (NSC 96-2221-E-006-259, NSC 96-2314-B-037-059) and a grant from the National Health Research Institutes (NHRI-EX97-9615EP) of Taiwan. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.