Figure 1.

Photobiomodulation (PBM) enhances the proliferation and self-renewal of mesenchymal stem cells (MSCs). (A) Cell proliferation assays using MSCs treated with or without PBM at the indicated light parameters. As an irradiance of 7.12 mW/cm² and a fluence of 1 J/cm² were considered most beneficial to stimulate MSC proliferation, the following experiments were conducted using this condition. (B) Mitochondrial membrane potential of unconditioned MSCs (MSC; open histogram) and PBM-treated MSCs (PBM-MSC; filled histogram), as detected by rhodamine 123 (Rh123) fluorescence. (C) Clonogenic colony-forming unit-fibroblast (CFU-f) assay for MSC and PBM-MSC groups based on 0.5% crystal violet staining. (D) Relative mRNA expression of stemness-related genes in MSCs analyzed by real-time reverse transcription-polymerase chain reaction (RT-PCR). Data are presented as the mean ± standard error of the mean (SEM); n ≥ 3 per group. * p < 0.05 compared to the control.