title: Low-level laser therapy (808 nm) reduces inflammatory response and oxidative stress in rat tibialis anterior muscle after cryolesion.
abstract: OBJECTIVE
  Muscle regeneration is a complex phenomenon, involving coordinated activation of several cellular responses. During this process, oxidative stress and consequent tissue damage occur with a severity that may depend on the intensity and duration of the inflammatory response. Among the therapeutic approaches to attenuate inflammation and increase tissue repair, low-level laser therapy (LLLT) may be a safe and effective clinical procedure. The aim of this study was to evaluate the effects of LLLT on oxidative/nitrative stress and inflammatory mediators produced during a cryolesion of the tibialis anterior (TA) muscle in rats.
  
  
  METHODS
  Sixty Wistar rats were randomly divided into three groups (n = 20): control (BC), injured TA muscle without LLLT (IC), injured TA muscle submitted to LLLT (IRI). The injured region was irradiated daily for 4 consecutive days, starting immediately after the lesion using a AlGaAs laser (continuous wave, 808 nm, tip area of 0.00785 cm(2) , power 30 mW, application time 47 seconds, fluence 180 J/cm(2) ; 3.8 mW/cm(2) ; and total energy 1.4 J). The animals were sacrificed on the fourth day after injury.
  
  
  RESULTS
  LLLT reduced oxidative and nitrative stress in injured muscle, decreased lipid peroxidation, nitrotyrosine formation and NO production, probably due to reduction in iNOS protein expression. Moreover, LLLT increased SOD gene expression, and decreased the inflammatory response as measured by gene expression of NF-kβ and COX-2 and by TNF-α and IL-1β concentration.
  
  
  CONCLUSIONS
  These results suggest that LLLT could be an effective therapeutic approach to modulate oxidative and nitrative stress and to reduce inflammation in injured muscle.
authors.affiliation: Laboratory of Electrothermophototherapy, Department of Phisiotherapy, University of São Carlos, São Carlos, SP, Brazil.
authors.forename: Lívia
authors.initials: L
authors.lastname: Assis
authors.forename: Ana I S
authors.initials: AI
authors.lastname: Moretti
authors.forename: Thalita B
authors.initials: TB
authors.lastname: Abrahão
authors.forename: Vivian
authors.initials: V
authors.lastname: Cury
authors.forename: Heraldo P
authors.initials: HP
authors.lastname: Souza
authors.forename: Michael R
authors.initials: MR
authors.lastname: Hamblin
authors.forename: Nivaldo A
authors.initials: NA
authors.lastname: Parizotto
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D003080:Cold Temperature; D015151:Immunoblotting; D018836:Inflammation Mediators / Q000378:metabolism*; D054023:Lasers, Semiconductor / Q000627:therapeutic use*; D008297:Male; D018482:Muscle, Skeletal / Q000293:injuries* / Q000502:physiology / Q000528:radiation effects; D018384:Oxidative Stress / Q000528:radiation effects*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction; D017695:Soft Tissue Injuries / Q000209:etiology / Q000503:physiopathology / Q000532:radiotherapy*; D016896:Treatment Outcome; D014945:Wound Healing / Q000528:radiation effects*
chemical_list: D015415:Biomarkers; D018836:Inflammation Mediators