The impact of non-toxic blue light (453 nm) on cellular antioxidative capacity, TGF-β1 signaling, and myofibrogenesis of human skin fibroblasts

J Photochem Photobiol B. 2020 Aug;209:111952. doi: 10.1016/j.jphotobiol.2020.111952. Epub 2020 Jul 6.


Studies have demonstrated that blue light induces biological effects, such as cell death, and inhibition of proliferation and differentiation. Since blue light at longer wavelength (>440 nm) exerts less injurious effects on cells than at shorter wavelengths, (400-440 nm), we have investigated the impact of non-toxic (LED) blue light at 453 nm wavelength on human skin fibroblasts (hsFBs). We found that besides its decreasing effects on the proliferation rate, repeated blue light irradiations (80 J/cm2) also significantly reduced TGF-β1-induced myofibrogenesis as shown by diminished α-SMA and EDA-FN expression accompanied by reduced protein expression and phosphorylation of ERK 1/2, SMAD 2/3, and p38-key players of TGF-β1-induced myofibrogenesis. In parallel, catalase protein expression, intracellular FAD concentrations as well as NADP+/NADPH ratio were reduced, whereas intracellular reactive oxygen species (ROS) were increased. We postulate that as a molecular mechanism downregulation of catalase and photoreduction of FAD induce intracellular oxidative stress which, in turn, affects the signaling factors of myofibrogenesis leading to a lower rate of α-SMA and EDA-FN expression and, therefore, myofibroblast formation. In conclusion, blue light even at longer wavelengths shows antifibrotic activity and may represent a suitable and safe approach in the treatment of fibrotic skin diseases including hypertrophic scarring and scleroderma.

Keywords: Antioxidative capacity; Blue light; Catalase; Differentiation; Fibroblast; Fibrotic skin diseases; Myofibrogenesis.

MeSH terms

  • Antioxidants / metabolism*
  • Cell Proliferation / radiation effects
  • Humans
  • Light*
  • Myofibroblasts / cytology
  • Myofibroblasts / radiation effects
  • Oxidative Stress
  • Signal Transduction / radiation effects*
  • Transforming Growth Factor beta1 / metabolism*


  • Antioxidants
  • TGFB1 protein, human
  • Transforming Growth Factor beta1