title: Inflammatory cytokines are suppressed by light-emitting diode irradiation of P. gingivalis LPS-treated human gingival fibroblasts: inflammatory cytokine changes by LED irradiation.
abstract: Human gingival fibroblasts (hGFs) play an important role in the inflammatory reaction to lipopolysaccharide (LPS) from P. gingivalis, which infects periodontal connective tissue. In addition, although light-emitting diode (LED) irradiation has been reported to have biostimulatory effects, including anti-inflammatory activity, the pathological mechanisms of these effects are unclear. This study examined the effects of 635-nm irradiation of P. gingivalis LPS-treated human gingival fibroblasts on inflammatory cytokine profiles and the mitogen-activated protein kinase (MAPK) pathway, which is involved in cytokine production. Gingival fibroblasts treated or not treated with P. gingivalis LPS were irradiated with 635-nm LED light, and cytokine profiles in the supernatant were assessed using a human inflammation antibody array. Expression of cyclooxyginase-2 (COX-2) protein and phosphorylation of extracellular signal-regulated kinase (ERK 1/2), p38, and c-Jun-N-terminal kinase (JNK) were assessed by Western-blot analysis to determine the effects on the MAPK pathway, and prostaglandin E(2) (PGE(2)) in the supernatant was measured using an enzyme-linked immunoassay. COX-2 protein expression and PGE(2) production were significantly increased in the LPS-treated group and decreased by LED irradiation. LPS treatment of gingival fibroblasts led to the increased release of the pro-inflammatory-related cytokines interleukin-6 (IL-6) and IL-8, whereas LED irradiation inhibited their release. Analysis of MAPK signal transduction revealed a considerable decrease in p38 phosphorylation in response to 635-nm radiation either in the presence or absence of LPS. In addition, 635-nm LED irradiation significantly promoted JNK phosphorylation in the presence of LPS. LED irradiation can inhibit activation of pro-inflammatory cytokines, mediate the MAPK signaling pathway, and may be clinically useful as an anti-inflammatory tool.
authors.affiliation: Department of Oral Pathology, 2nd stage of Brain Korea 21 for School of Dentistry, Dental Science Research Institute, Chonnam National University, Bug-Gu, Gwangju, 500-757, Korea.
authors.forename: HongRan
authors.initials: H
authors.lastname: Choi
authors.forename: WonBong
authors.initials: W
authors.lastname: Lim
authors.forename: InAe
authors.initials: I
authors.lastname: Kim
authors.forename: JiSun
authors.initials: J
authors.lastname: Kim
authors.forename: YoungJong
authors.initials: Y
authors.lastname: Ko
authors.forename: Hyukil
authors.initials: H
authors.lastname: Kwon
authors.forename: SangWoo
authors.initials: S
authors.lastname: Kim
authors.forename: K M Ahsan
authors.initials: KM
authors.lastname: Kabir
authors.forename: Xiaojie
authors.initials: X
authors.lastname: Li
authors.forename: Oksu
authors.initials: O
authors.lastname: Kim
authors.forename: YoungJoon
authors.initials: Y
authors.lastname: Lee
authors.forename: SeoYune
authors.initials: S
authors.lastname: Kim
authors.forename: OkJoon
authors.initials: O
authors.lastname: Kim
mesh_terms: D015153:Blotting, Western; D018929:Cell Culture Techniques; D051546:Cyclooxygenase 2 / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism*; D015232:Dinoprostone / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005347:Fibroblasts / Q000276:immunology* / Q000378:metabolism; D005881:Gingiva / Q000166:cytology / Q000276:immunology* / Q000528:radiation effects; D006801:Humans; D054023:Lasers, Semiconductor / Q000627:therapeutic use*; D008070:Lipopolysaccharides / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000276:immunology; D048052:Mitogen-Activated Protein Kinase 3 / Q000276:immunology; D010510:Periodontal Diseases / Q000276:immunology* / Q000378:metabolism; D016966:Porphyromonas gingivalis / Q000528:radiation effects*; D015398:Signal Transduction
chemical_list: D016207:Cytokines; D008070:Lipopolysaccharides; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D048052:Mitogen-Activated Protein Kinase 3; D015232:Dinoprostone