title: BIOMECHANICAL AND HISTOLOGICAL ANALYSIS OF THE GASTROCNEMIUS IN RATS SUBJECTED TO MUSCLE INJURY AND TREATMENT WITH LOW-LEVEL LASER THERAPY.
abstract: OBJECTIVE
  To mechanically and histologically evaluate the application of low-level laser therapy to the reparative process on lesions caused by impact on the gastrocnemius muscles of rats.
  
  
  METHODS
  45 female Wistar rats were divided into three groups (n=15/ group): C (control, no lesion), ML (muscle lesion) and ML-L (muscle lesion and laser therapy). The experimental muscle lesion was produced by letting a 250 g load drop from a height of 30 cm, directly onto the muscle. The animals in the ML-L group were subjected to application of 960 nm laser, 2 J/cm(2), on the lesion site, for three days, twice a day. Mechanical tests were performed on an Emic(®) universal testing machine.
  
  
  RESULTS
  The mean values for the maximum force were: 35.70 (± 2.69) N in group C, 31.77 (± 2.59) N in group ML and 34.36 (± 3.63) N in group ML-L, with a statistically significant difference between groups C and ML (p < 0.05). The mean values for relative stiffness were: 3.75 (± 0.98) N/mm in group C, 3.84 (± 0.32) N/mm in group ML and 4.43 (± 0.68) N/mm in group ML-L, with no statistically significant differences (p>0.05). Histological analysis showed the presence of blood vessels in group ML-L and hematomas during the repair process.
  
  
  CONCLUSIONS
  Laser therapy had a positive effect on the regeneration process of the muscle injury.
authors.affiliation: Postgraduate Student in the Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus, Ribeirão Preto School of Medicine, USP.
authors.forename: Mauricio José
authors.initials: MJ
authors.lastname: Falcai
authors.affiliation: Postgraduate Student in the Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus, Ribeirão Preto School of Medicine, USP.
authors.forename: Vanessa Vilela
authors.initials: VV
authors.lastname: Monte-Raso
authors.affiliation: Postgraduate Student in the Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus, Ribeirão Preto School of Medicine, USP.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Okubo
authors.affiliation: Postgraduate Student in the Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus, Ribeirão Preto School of Medicine, USP.
authors.forename: Ariane
authors.initials: A
authors.lastname: Zamarioli
authors.affiliation: Postgraduate Student in the Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus, Ribeirão Preto School of Medicine, USP.
authors.forename: Leonardo César
authors.initials: LC
authors.lastname: Carvalho
authors.affiliation: PhD. Professor in the Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus, Ribeirao Preto School of Medicine, USP.
authors.forename: Antõnio Carlos
authors.initials: AC
authors.lastname: Shimano
keywords: Laser therapy, low-level; Rats; Regeneration