title: Low-level laser therapy (LLLT; 780 nm) acts differently on mRNA expression of anti- and pro-inflammatory mediators in an experimental model of collagenase-induced tendinitis in rat.
abstract: Low-level laser therapy (LLLT) has been found to produce anti-inflammatory effects in a variety of disorders. Tendinopathies are directly related to unbalance in expression of pro- and anti-inflammatory cytokines which are responsible by degeneration process of tendinocytes. In the current study, we decided to investigate if LLLT could reduce mRNA expression for TNF-α, IL-1β, IL-6, TGF-β cytokines, and COX-2 enzyme. Forty-two male Wistar rats were divided randomly in seven groups, and tendinitis was induced with a collagenase intratendinea injection. The mRNA expression was evaluated by real-time PCR in 7th and 14th days after tendinitis. LLLT irradiation with wavelength of 780 nm required for 75 s with a dose of 7.7 J/cm(2) was administered in distinct moments: 12 h and 7 days post tendinitis. At the 12 h after tendinitis, the animals were irradiated once in intercalate days until the 7th or 14th day in and them the animals were killed, respectively. In other series, 7 days after tendinitis, the animals were irradiated once in intercalated days until the 14th day and then the animals were killed. LLLT in both acute and chronic phases decreased IL-6, COX-2, and TGF-β expression after tendinitis, respectively, when compared to tendinitis groups: IL-6, COX-2, and TGF-β. The LLLT not altered IL-1β expression in any time, but reduced the TNF-α expression; however, only at chronic phase. We conclude that LLLT administered with this protocol reduces one of features of tendinopathies that is mRNA expression for pro-inflammatory mediators.
authors.affiliation: Institute of Research and Development, Av. Shishima Hifumi, 2911, Urbanova, CEP, 12.244-000, São José dos Campos, SP, Brazil.
authors.forename: Débora
authors.initials: D
authors.lastname: Pires
authors.forename: Murilo
authors.initials: M
authors.lastname: Xavier
authors.forename: Tiago
authors.initials: T
authors.lastname: Araújo
authors.forename: José Antônio
authors.initials: JA
authors.lastname: Silva
authors.forename: Flavio
authors.initials: F
authors.lastname: Aimbire
authors.forename: Regiane
authors.initials: R
authors.lastname: Albertini
mesh_terms: D000818:Animals; D001483:Base Sequence; D017364:Collagenases / Q000008:administration & dosage; D051546:Cyclooxygenase 2 / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D004195:Disease Models, Animal; D015870:Gene Expression; D018836:Inflammation Mediators / Q000378:metabolism*; D053583:Interleukin-1beta / Q000235:genetics; D015850:Interleukin-6 / Q000235:genetics; D028022:Low-Level Light Therapy; D008297:Male; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D052256:Tendinopathy / Q000139:chemically induced / Q000235:genetics* / Q000378:metabolism / Q000532:radiotherapy*; D013710:Tendons / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D016212:Transforming Growth Factor beta / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
chemical_list: D017931:DNA Primers; D018836:Inflammation Mediators; D053583:Interleukin-1beta; D015850:Interleukin-6; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D014409:Tumor Necrosis Factor-alpha; D051546:Cyclooxygenase 2; D017364:Collagenases