Subcutaneous Injection of Conditioned Medium from Photobiomodulation- Treated Adipose-Derived Stromal Cells Promotes Hair Growth in Mice

The purpose of this study was to investigate whether subcutaneous injection of conditioned medium from photobiomodulation (PBM) irradiated adipose-derived stromal cells (ASCs) could stimulate hair growth in mice. Human ASCs were plated on cell culture dishes at a concentration of 2 × 10⁴ cells/cm² and allowed to adhere at 37°C. Light emitting diode (660 nm, 50 mW/cm²) was applied for 10 min daily from day 1 to day 10. Conditioned medium (CM) fractions were collected from PBM-irradiated ASCs to yield (PBM-CM). They were centrifuged at 13,000 g for 10 min at 4°C and stored prior to use for ELISA, protein assay, or in vivo assays. Forty-one growth factors in PBM-CM from cells cultured under PBM or non-PBM conditions were analyzed. Survival, differentiation and secretion of vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), and hepatocyte growth factor (HGF) of PBM-CM were evaluated by western blot. Secretion of insulin-like growth (IGF), platelet-derived growth factor (PDGF), and insulin-like growth factor binding protein (IGFBP) were significantly increased by PBM. PBM-CM enhanced hair growth in a hair loss model compared to non-irradiated ASC-CM or Phosphate-buffered saline (PBS). PBM is an effective biostimulator of ASC-CM in hair regrowth by enhancing secretion of growth factors. Thus, PBM-CM has the potential to stimulate hair growth and treat alopecia.