title: Activation of the extracellular signal-regulated kinase signal pathway by light emitting diode irradiation.
abstract: Irradiation by light emitting diode (LED) promotes fibroblast proliferation and wound healing. However, its mechanism is still unknown. The purpose of this study was to clarify the mechanism of fibroblast proliferation by LED irradiation. Cultured NIH3T3 fibroblasts from normal mice were irradiated by LED with a center wavelength of 627 nm. LED irradiation was performed with an energy density of 4 J/cm(2), at subculture and 24 h later. The expression of several growth factors and their receptors was analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR): platelet-derived growth factor (PDGF)-A, PDGF-B, and PDGF-C, transforming growth factor-beta (TGF-beta), basic fibroblast growth factor (bFGF), PDGF-alpha receptor, and TGF-beta receptor. Then, the activation of the extracellular signal-regulated kinase (ERK) pathway was examined by Western blotting with and without the PDGF receptor inhibitor. LED irradiation induced cell growth of NIH3T3 fibroblasts. The expression of PDGF-C had significantly increased in the irradiated group (P < 0.01). Although strong activation of the ERK pathway was observed in the irradiated group, its activation was completely suppressed by the PDGF receptor inhibitor. We concluded that LED irradiation promotes fibroblast proliferation by increasing autocrine production of PDGF-C and activating the ERK pathway through phosphorylation of the PDGF receptor.
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Kanazawa University, 13-1 Takaramachi, Kanazawa, 920-8641, Japan. komi0728@m2.spacelan.ne.jp
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Komine
authors.forename: Kazuo
authors.initials: K
authors.lastname: Ikeda
authors.forename: Kaoru
authors.initials: K
authors.lastname: Tada
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Hashimoto
authors.forename: Naotoshi
authors.initials: N
authors.lastname: Sugimoto
authors.forename: Katsuro
authors.initials: K
authors.lastname: Tomita
mesh_terms: D000818:Animals; D002455:Cell Division / Q000528:radiation effects; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000528:radiation effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D016222:Fibroblast Growth Factor 2 / Q000032:analysis; D005347:Fibroblasts / Q000528:radiation effects; D008027:Light; D008222:Lymphokines / Q000032:analysis; D051379:Mice; D010982:Platelet-Derived Growth Factor / Q000032:analysis; D020574:Proto-Oncogene Proteins c-sis / Q000032:analysis; D017479:Receptors, Platelet-Derived Growth Factor / Q000032:analysis; D018125:Receptors, Transforming Growth Factor beta / Q000032:analysis; D015398:Signal Transduction / Q000528:radiation effects; D016212:Transforming Growth Factor beta / Q000032:analysis
chemical_list: D008222:Lymphokines; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D018125:Receptors, Transforming Growth Factor beta; D016212:Transforming Growth Factor beta; C075278:platelet-derived growth factor A; C411423:platelet-derived growth factor C; D016222:Fibroblast Growth Factor 2; D017479:Receptors, Platelet-Derived Growth Factor; D048049:Extracellular Signal-Regulated MAP Kinases