title: Increased fibroblast proliferation induced by light emitting diode and low power laser irradiation.
abstract: OBJECTIVE
  As Light Emitting Diode (LED) devices are commercially introduced as an alternative for Low Level Laser (LLL) Therapy, the ability of LED in influencing wound healing processes at cellular level was examined.
  
  
  METHODS
  Cultured fibroblasts were treated in a controlled, randomized manner, during three consecutive days, either with an infrared LLL or with a LED light source emitting several wavelengths (950 nm, 660 nm and 570 nm) and respective power outputs. Treatment duration varied in relation to varying surface energy densities (radiant exposures).
  
  
  RESULTS
  Statistical analysis revealed a higher rate of proliferation (p < 0.001) in all irradiated cultures in comparison with the controls. Green light yielded a significantly higher number of cells, than red (p < 0.001) and infrared LED light (p < 0.001) and than the cultures irradiated with the LLL (p < 0.001); the red probe provided a higher increase (p < 0.001) than the infrared LED probe and than the LLL source.
  
  
  CONCLUSIONS
  LED and LLL irradiation resulted in an increased fibroblast proliferation in vitro. This study therefore postulates possible stimulatory effects on wound healing in vivo at the applied dosimetric parameters.
authors.affiliation: Department of Rehabilitation Sciences and Physiotherapy, Ghent University, 9000 Ghent, Belgium. elke.vinck@ugent.be
authors.forename: Elke M
authors.initials: EM
authors.lastname: Vinck
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Cagnie
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Cornelissen
authors.forename: Heidi A
authors.initials: HA
authors.lastname: Declercq
authors.forename: Dirk C
authors.initials: DC
authors.lastname: Cambier
mesh_terms: D000818:Animals; D002452:Cell Count; D002455:Cell Division / Q000528:radiation effects; D002478:Cells, Cultured; D002642:Chick Embryo; D004307:Dose-Response Relationship, Radiation; D005347:Fibroblasts / Q000166:cytology* / Q000528:radiation effects*; D007259:Infrared Rays; D008027:Light; D028022:Low-Level Light Therapy; D013997:Time Factors