title: Low-Level Light Therapy with 410 nm Light Emitting Diode Suppresses Collagen Synthesis in Human Keloid Fibroblasts: AnIn VitroStudy.
abstract: BACKGROUND
  Keloids are characterized by excessive collagen deposition in the dermis, in which transforming growth factor β (TGF-β)/Smad signaling plays an important role. Low-level light therapy (LLLT) is reported as effective in preventing keloids in clinical reports, recently. To date, studies investigating the effect of LLLT on keloid fibroblasts are extremely rare.
  
  
  OBJECTIVE
  We investigated the effect of LLLT with blue (410 nm), red (630 nm), and infrared (830 nm) light on the collagen synthesis in keloid fibroblasts.
  
  
  METHODS
  Keloid fibroblasts were isolated from keloid-revision surgery samples and irradiated using 410-, 630-, 830-nm light emitting diode twice, with a 24-hour interval at 10 J/cm2. After irradiation, cells were incubated for 24 and 48 hours and real-time quantitative reverse transcription polymerase chain reaction was performed. Western blot analysis was also performed in 48 hours after last irradiation. The genes and proteins of collagen type I, TGF-β1, Smad3, and Smad7 were analyzed.
  
  
  RESULTS
  We observed no statistically significant change in the viability of keloid fibroblasts after irradiation. Collagen type I was the only gene whose expression significantly decreased after irradiation at 410 nm when compared to the non-irradiated control. Western blot analysis showed that LLLT at 410 nm lowered the protein levels of collagen type I compared to the control.
  
  
  CONCLUSIONS
  LLLT at 410 nm decreased the expression of collagen type I in keloid fibroblasts and might be effective in preventing keloid formation in their initial stage.
authors.affiliation: Department of Dermatology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: Hyun Soo
authors.initials: HS
authors.lastname: Lee
authors.affiliation: Department of Dermatology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: Soo-Eun
authors.initials: SE
authors.lastname: Jung
authors.affiliation: Department of Dermatology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: Sue Kyung
authors.initials: SK
authors.lastname: Kim
authors.affiliation: Department of Biochemistry, Ajou University School of Medicine, Suwon, Korea.
authors.forename: You-Sun
authors.initials: YS
authors.lastname: Kim
authors.affiliation: Laboratory of Cell Biology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: Seonghyang
authors.initials: S
authors.lastname: Sohn
authors.affiliation: Department of Dermatology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: You Chan
authors.initials: YC
authors.lastname: Kim
keywords: Collagen type I; Keloid fibroblast; Low-level light therapy