title: Anti-inflammatory effects of low-level light emitting diode therapy on Achilles tendinitis in rats.
abstract: OBJECTIVE
  The present study investigated the effects of low-level light emitting diode (LED) therapy (880 +/- 10 nm) on inflammatory process in a experimental model of Achilles tendinitis induced by collagenase.
  
  
  METHODS
  Fifty-six male Wistar were separated into seven groups (n = 8), three groups in the experimental period of 7 days and four groups in the experimental period of 14 days, the control group (CONT), tendinitis group (TEND), LED therapy group (LEDT) for both experimental periods, and LED therapy group 7th to 14th day (LEDT delay) for 14 days experimental period. The LED parameters was 22 mW CW of optical output power, distributed in an irradiation area of 0.5 cm(2), with an irradiation time of 170 seconds, the applied energy density was 7.5 J/cm(2) in contact. The therapy was initiated 12 hours after the tendinitis induction, with a 48-hour interval between the irradiations. The histological analysis and inflammatory mediators were quantified.
  
  
  RESULTS
  Our results showed that LED decreases the inflammatory cells influx and mRNA expression to IL-1 beta, IL-6, tumor necrosis factor-alpha (TNF-alpha) in both phase, and cyclooxygenase-2 (COX-2) just in initial phase (P < 0.05).
  
  
  CONCLUSIONS
  Our results suggest that the anti-inflammatory therapy with low-power LED (880 nm) enhanced the tissue response in all groups. We can conclude that the LED was able to reduce signs of inflammation in collagenase-induced tendinitis in rats by reducing the number of inflammatory cells and decrease mRNA expression of cytokines.
authors.affiliation: Institute of Research and Development, IP&D, Vale do Paraiba University, UNIVAP, Av. Shishima Hifumi, 2911, 12244-000 São José dos Campos, São Paulo, Brazil.
authors.forename: Murilo
authors.initials: M
authors.lastname: Xavier
authors.forename: Débora Rodrigues
authors.initials: DR
authors.lastname: David
authors.forename: Renato Aparecido
authors.initials: RA
authors.lastname: de Souza
authors.forename: Arthur Nascimento
authors.initials: AN
authors.lastname: Arrieiro
authors.forename: Humberto
authors.initials: H
authors.lastname: Miranda
authors.forename: Eduardo Tadeu
authors.initials: ET
authors.lastname: Santana
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Silva
authors.forename: Miguel Angel Castillo
authors.initials: MA
authors.lastname: Salgado
authors.forename: Flávio
authors.initials: F
authors.lastname: Aimbire
authors.forename: Regiane
authors.initials: R
authors.lastname: Albertini
mesh_terms: D000125:Achilles Tendon / Q000473:pathology / Q000503:physiopathology*; D000818:Animals; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D008297:Male; D010789:Phototherapy; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D052256:Tendinopathy / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*
chemical_list: D016207:Cytokines; D012333:RNA, Messenger; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human