Boosting osteoblast differentiation: enhancing the effects of low-level blue laser therapy on human embryonic stem cell-derived mesenchymal stem cells to improve viability and calcium deposition.

Abstract

Mesenchymal stem cells (MSCs) are widely studied for their regenerative capacities in bone tissue repair. Low-level laser therapy (LLLT) has emerged as a promising method to stimulate stem cell proliferation, viability, and differentiation. In this study, we focus on how low-level blue-laser treatment (457 nm) affects human embryonic stem cell-derived mesenchymal stem cells (hESC-MSCs) at various energy densities, highlighting its potential to enhance osteogenic differentiation for clinical applications in treating osteoporosis. To determine how low-level blue-laser treatment at various energy densities (0.5-5.0 J/cm²) influences the proliferation, viability, migration, and osteogenic differentiation of hESC-MSCs. hESC-MSCs were cultured to near confluence, then irradiated at doses ranging from 0.5 to 5.0 J/cm². Cell proliferation, viability, and migration were assessed at 72 h. Flow cytometry evaluated CD146 expression, and Alkaline phosphate (ALP) activity was measured. Osteogenic gene expression (Runx2, ALP, BMP2, BMP4, and osteonectin) and in vitro mineralization were also examined. Blue-laser treatment at 0.5-3.5 J/cm² significantly increased cell proliferation (p < 0.01) and viability (p < 0.05), while migration was enhanced at 0.5-2.5 J/cm² (p < 0.001). CD146 expression rose at 0.5, 1.0, and 2.0 J/cm², with a 1.9-fold increase in ALP activity at 2.0 J/cm². Osteogenic markers and mineralization were likewise upregulated at 2.0 J/cm², indicating enhanced osteoblast differentiation. These findings indicate that LLLT combined with a blue laser results in changes in various biological processes at the cellular and genetic levels in hESC-MSCs, indicating that these cells are sensitive to blue laser treatment. Thus, these results demonstrate that hMSCs are responsive to blue-laser treatment, which may be used in the clinic to treat osteoporosis.