Inhibitory effect of 660-nm LED on melanin synthesis in in vitro and in vivo

Photodermatol Photoimmunol Photomed. 2017 Jan;33(1):49-57. doi: 10.1111/phpp.12276. Epub 2016 Nov 3.


Background: Skin hyperpigmentary disorders including postinflammatory hyperpigmentation, melasma, solar lentigines, and conditions like freckles are common. The light-emitting diodes (LEDs) are the latest category of nonthermal and noninvasive phototherapy to be considered in skin pigmentation disorder treatment.

Purpose: The purpose of this study was to investigate the effects of 660-nm LED on inhibition of melanogenesis. We investigated whether a 660-nm LED affected melanin synthesis in in vitro and in vivo models, and we explored the mechanisms involved.

Methods: The inhibitory effect of 660-nm LED on melanin synthesis was evaluated in B16F10 cells and HRM-2 melanin-possessing hairless mice were used to evaluate the antimelanogenic effects of 660-nm LED.

Results: Interestingly, 660-nm LED inhibited alpha-melanocyte-stimulating hormone-induced tyrosinase activity in B16F10 cells. We also found that 660-nm LED decreased MITF and tyrosinase expression and induced the activation of ERK. These findings suggest that the depigmenting effects of 660-nm LED result from downregulation of MITF and tyrosinase expression due to increased ERK activity. The 660-nm LED reduced UVB-induced melanogenesis in the skin of HRM-2 via downregulation of tyrosinase and MITF.

Conclusion: These findings suggest 660-nm LED is a potentially depigmentation strategy.

Keywords: 660-nm wavelength; B16F10 cell; HRM-2; light-emitting diode; melanogenesis.

MeSH terms

  • Animals
  • Cell Line, Tumor
  • Intramolecular Oxidoreductases / metabolism
  • Light*
  • MART-1 Antigen / analysis
  • Melanins / biosynthesis*
  • Membrane Glycoproteins / metabolism
  • Mice
  • Mice, Hairless
  • Microphthalmia-Associated Transcription Factor / analysis
  • Microphthalmia-Associated Transcription Factor / metabolism*
  • Mitogen-Activated Protein Kinase 1 / metabolism
  • Monophenol Monooxygenase / analysis
  • Monophenol Monooxygenase / metabolism*
  • Oxidoreductases / metabolism
  • Protein Biosynthesis / radiation effects*
  • S100 Proteins / analysis
  • Skin / chemistry
  • Skin / radiation effects*
  • alpha-MSH / metabolism


  • MART-1 Antigen
  • Melanins
  • Membrane Glycoproteins
  • Microphthalmia-Associated Transcription Factor
  • Mitf protein, mouse
  • Mlana protein, mouse
  • S100 Proteins
  • alpha-MSH
  • Oxidoreductases
  • Tyrp1 protein, mouse
  • Monophenol Monooxygenase
  • Mapk1 protein, mouse
  • Mitogen-Activated Protein Kinase 1
  • Intramolecular Oxidoreductases
  • dopachrome isomerase