title: Inhibition of fibroblast proliferation in vitro using red light-emitting diodes.
abstract: BACKGROUND
  Red light is part of the visible light spectrum. The effects of light-emitting diode (LED)-generated red light on human skin are not well-characterized.
  
  
  OBJECTIVE
  To study the effect of red LED-generated low-level light therapy (LLLT) on fibroblast proliferation and viability in vitro.
  
  
  METHODS
  Irradiation of normal human skin fibroblasts using red LED panels was performed in vitro, and modulation of proliferation and viability was quantified using trypan blue dye exclusion assay.
  
  
  RESULTS
  Statistically significant decreases in cell proliferation were noted at the following fluences (time): 160 J/cm2 (30 minutes, 34 seconds), 320 J/cm2 (61 minutes, 07 seconds) and 640 J/cm2 (122 minutes, 14 seconds) (Figure 1). Irradiation at the 160- (98.5 ± 1.2%) and 320-J/cm2 (98.0 ± 3.1%) doses did not significantly alter viability.
  
  
  CONCLUSIONS
  At certain fluences, red LLLT can effectively inhibit fibroblast proliferation in vitro without altering viability and holds promise for the treatment of scars and other proliferative skin diseases.
authors.affiliation: Dermatology Service, Sacramento Veteran Affairs Medical Center, Mather, California, USA.
authors.forename: Hadar
authors.initials: H
authors.lastname: Lev-Tov
authors.forename: Andrew
authors.initials: A
authors.lastname: Mamalis
authors.forename: Neil
authors.initials: N
authors.lastname: Brody
authors.forename: Daniel
authors.initials: D
authors.lastname: Siegel
authors.forename: Jared
authors.initials: J
authors.lastname: Jagdeo
mesh_terms: D049109:Cell Proliferation / Q000528:radiation effects*; D002470:Cell Survival; D005347:Fibroblasts / Q000166:cytology / Q000528:radiation effects*; D006801:Humans; D007259:Infrared Rays / Q000627:therapeutic use; D054023:Lasers, Semiconductor; D028022:Low-Level Light Therapy; D012867:Skin / Q000528:radiation effects*