title: A study of Q-switched Nd:YAG laser irradiation and paracrine function in human skin cells.
abstract: OBJECTIVE
  This preliminary laboratory-based study looks at the paracrine release from human skin cells subject to sublethal Q-switched Nd:YAG 532 nm laser irradiation.
  
  
  METHODS
  Human dermal fibroblast and keratinocyte cultures were exposed to sublethal energy using the Nd:YAG 532 nm laser. Altered gene expression was then screened using RT-PCR for a range of paracrine factors known to affect melanogenesis, basic fibroblast growth factor (b-FGF), hepatocyte growth factor (HGF), stem cell factor (SCF), melanocyte stimulating hormone (MSH), endothelin-1 (ET-1), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha) and protease-activated receptor-2 (PAR-2). Enzyme-linked immunosorbent assay (ELISA) was used to confirm protein production. Conditioned medium was used to assess altered melanogenesis in a melanoma cell line.
  
  
  RESULTS
  Fibroblasts exposed to sublethal radiation showed upregulation of b-FGF, HGF and SCF. This contrasts with keratinocytes which showed upregulation of IL-6. Elevated protein levels of b-FGF and SCF were confirmed by ELISA assay. Conditioned fibroblast medium was shown to stimulate melanogenesis in a melanoma cell line.
  
  
  CONCLUSIONS
  This preliminary laboratory study reports, for the first time, specific gene upregulation using the Q-switched Nd:YAG 532 nm laser.
authors.affiliation: Division of Plastic and Reconstructive Surgery, Department of Surgery, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong. andrewburd@surgery.cuhk.edu.hk
authors.forename: Andrew
authors.initials: A
authors.lastname: Burd
authors.forename: Ningwen
authors.initials: N
authors.lastname: Zhu
authors.forename: Vincent K M
authors.initials: VK
authors.lastname: Poon
mesh_terms: D002478:Cells, Cultured; D017931:DNA Primers; D004797:Enzyme-Linked Immunosorbent Assay; D005346:Fibroblast Growth Factors / Q000235:genetics / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism / Q000528:radiation effects; D006133:Growth Substances / Q000235:genetics / Q000378:metabolism*; D017228:Hepatocyte Growth Factor / Q000235:genetics / Q000378:metabolism; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism / Q000528:radiation effects; D028022:Low-Level Light Therapy; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012867:Skin / Q000166:cytology* / Q000528:radiation effects*; D019089:Stem Cell Factor / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D017931:DNA Primers; D006133:Growth Substances; D019089:Stem Cell Factor; D005346:Fibroblast Growth Factors; D017228:Hepatocyte Growth Factor