title: Inhibitory effect of 660-nm LED on melanin synthesis in in vitro and in vivo.
abstract: 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.
  
  
  OBJECTIVE
  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.
  
  
  CONCLUSIONS
  These findings suggest 660-nm LED is a potentially depigmentation strategy.
authors.affiliation: Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Korea.|Department of Medicine, Graduate School, Chung-Ang University, Seoul, Korea.
authors.forename: Chang Taek
authors.initials: CT
authors.lastname: Oh
authors.affiliation: Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Korea.
authors.forename: Tae-Rin
authors.identifier: http://orcid.org/0000-0002-9892-7714
authors.initials: TR
authors.lastname: Kwon
authors.affiliation: Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Korea.
authors.forename: Eun Ja
authors.initials: EJ
authors.lastname: Choi
authors.affiliation: Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Korea.
authors.forename: Soon Re
authors.initials: SR
authors.lastname: Kim
authors.affiliation: Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Korea.
authors.forename: Joon
authors.initials: J
authors.lastname: Seok
authors.affiliation: Department of Otorhinolaryngology, Chung-Ang University College of Medicine, Seoul, Korea.
authors.forename: Seog Kyun
authors.initials: SK
authors.lastname: Mun
authors.affiliation: Department of Dermatology, College of Medicine, Catholic Kwandong University, International St. Mary's Hospital, Incheon, Korea.
authors.forename: Kwang Ho
authors.initials: KH
authors.lastname: Yoo
authors.affiliation: Medical IT Convergence Research Center, Korea Electronics Technology Institute, Gyeonggi-do, Korea.
authors.forename: Yeon Shik
authors.initials: YS
authors.lastname: Choi
authors.affiliation: Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Korea.
authors.forename: Sun Young
authors.initials: SY
authors.lastname: Choi
authors.affiliation: Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Korea.|Department of Medicine, Graduate School, Chung-Ang University, Seoul, Korea.
authors.forename: Beom Joon
authors.initials: BJ
authors.lastname: Kim
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D019746:Intramolecular Oxidoreductases / Q000378:metabolism; D008027:Light; D058965:MART-1 Antigen / Q000032:analysis; D008543:Melanins / Q000096:biosynthesis*; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D008812:Mice, Hairless; D051739:Microphthalmia-Associated Transcription Factor / Q000032:analysis / Q000378:metabolism*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D014442:Monophenol Monooxygenase / Q000032:analysis / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism; D014176:Protein Biosynthesis / Q000528:radiation effects*; D009418:S100 Proteins / Q000032:analysis; D012867:Skin / Q000737:chemistry / Q000528:radiation effects*; D000521:alpha-MSH / Q000378:metabolism
chemical_list: D058965:MART-1 Antigen; D008543:Melanins; D008562:Membrane Glycoproteins; D051739:Microphthalmia-Associated Transcription Factor; C497235:Mitf protein, mouse; C548668:Mlana protein, mouse; D009418:S100 Proteins; D000521:alpha-MSH; D010088:Oxidoreductases; C079621:Tyrp1 protein, mouse; D014442:Monophenol Monooxygenase; C535148:Mapk1 protein, mouse; D019950:Mitogen-Activated Protein Kinase 1; D019746:Intramolecular Oxidoreductases; C042501:dopachrome isomerase
keywords: 660-nm wavelength; B16F10 cell; HRM-2; light-emitting diode; melanogenesis