Inflammatory cytokines are suppressed by light-emitting diode irradiation of P. gingivalis LPS-treated human gingival fibroblasts

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.

Mechanisms and applications of the anti-inflammatory effects of photobiomodulation

“…In the indirect irradiation group, phosphorylation of C-Raf and Erk1/2 increased. In another study [49] the same group used a similar system (direct PBM on HGF + LPS) and showed that 635 nm PBM reduced IL6, IL8, p38 phosphorylation, and increased JNK phosphorylation. They explained the activation of JNK by the growth promoting effects of PBM.…”

Irradiation by light‐emitting diode light as an adjunct to facilitate healing of experimental periodontitis in vivo

“…It has been shown in vitro that inflammation elicited by Porphyromonas gingivalis LPS ( Pg ‐LPS) can be suppressed by irradiating human gingival fibroblasts with visible red (635–670 nm) light (10). In this study, we devised a technique to directly irradiate the diseased gingival tissue with 660 nm LED light at a range of energy densities after debridement and detoxification in vivo .…”

Effects of light-emitting diodes phototherapy on autonomic modulation of footballers

“…a) efeito do grupo; b) efeito do tempo; c) interação grupo tempo. marcadamente das citocinas próinfl amatórias 21 , as quais levam a diminuição na atividade autonômica, sobretudo vagal [24][25] . No entanto, não observamos efeitos da LED fototerapia no presente estudo comparada com a situação placebo.…”

“…Seu mecanismo de ação se dá mediante aumento da atividade metabólica intracelular 19 aliada a uma diminuição da produção de agentes pró-infl amatórios [19][20][21][22][23] e marcadores de dano muscular 23 , e a diminuição desses, por sua vez, pode acarretar efeitos sistêmicos traduzidos em aumento na atividade parassimpática [24][25] e diminuição do estresse percebido [26][27] . Embora inconclusivos, principalmente pela escolha dos metabólitos (ex: creatina quinase e lactato sanguíneo), modelo de exercício e aplicação de delineamento tranversais, estudos apontam para um efeito positivo da fototerapia.…”