title: Low level laser therapy on experimental myopathy.
abstract: OBJECTIVE
  The aim of the present work was to study the effect of Helium-Neon (HeNe) and Gallium Arsenide (GaAs) laser upon nitric oxide (NO) plasma levels, an inflammatory biomarker associated with oxidative stress, in rats with experimental myopathy. These were evaluated through histological assessment.
  
  
  METHODS
  The groups studied were: (A) control (intact rats that received LLLT sham exposures), (B) rats with myopathy and sacrificed at 24 h later, (C) rats with myopathy and sacrificed 8 days later, (D) rats with myopathy and treated with HeNe laser, (E) rats with myopathy and treated with GaAs laser, (F) intact rats treated with HeNe laser and (G) intact rats treated with GaAs laser. Myopathy was induced by injecting 50μl of 1% carrageenan λ (type IV) in the left gastrocnemius muscle. Low Level Laser Therapy (LLLT) was applied with 9.5 J.cm(-2) daily for 10 consecutive days with each laser. The determination of the NO was made by spectrophotometry. The muscles were stained with Hematoxylin-Eosin and examined by optic microscopy. Quantitative variables were statistically analyzed by the Fisher test, and categorical by applying Pearson's Chi Squared test at p <0.05 for all cases.
  
  
  RESULTS
  In groups B and C, NO was significantly increased compared to groups A, D, E, F and G (p<0.05). In group C, the percentage of area with inflammatory infiltration was significantly increased compared to the other groups (p<0.001).
  
  
  CONCLUSIONS
  LLLT decreased plasma levels of NO in rats with experimental myopathies and significant muscle recovery.
authors.affiliation: Cátedra de Física Biomédica. Facultad de Ciencias Médicas. Universidad Nacional de Córdoba. Santa Rosa 1085. (5000) Córdoba, Argentina.
authors.forename: Soledad
authors.initials: S
authors.lastname: Dávila
authors.forename: María Belén
authors.initials: MB
authors.lastname: Vignola
authors.forename: David
authors.initials: D
authors.lastname: Cremonezzi
authors.forename: Juan C
authors.initials: JC
authors.lastname: Simes
authors.forename: Fernando
authors.initials: F
authors.lastname: Soriano
authors.forename: Vilma R
authors.initials: VR
authors.lastname: Campana
keywords: Gallium Arsenide; Helium Neon; LLLT; myopathy; nitric oxide