title: LLLT actives MMP-2 and increases muscle mechanical resistance after nerve sciatic rat regeneration.
abstract: The purpose of this study was to analyze the low-level laser therapy (LLLT) on metalloproteinase expression and the mechanical strength of skeletal muscle regeneration after peripheral nerve injury. Rats were subjected to crush injury of the right sciatic nerve, followed by LLLT (830 nm, 35, 70, 140, and 280 J/cm2) for 21 consecutive days. Functional gait analysis was performed at weekly intervals and the animals were sacrificed after the last evaluation at day 21 for collection of the gastrocnemius muscles, which were submitted to analysis of resistance, and the tibialis anterior, for evaluation of metalloproteinase-2 (MMP-2). The results were statistically analyzed at a significance level of 5%. The irradiated groups showed a significant decrease in the sciatic functional index and a significant increase in the mechanical strength when compared to the injured group with no treatment (p < 0.05), with no significant difference among the energy densities used. While no difference among groups was observed for the activity of MMP-2 in pro-active band, at the intermediate band, the activity was significantly higher (p < 0.05) for the groups irradiated with 35, 70, and 140 J/cm2, and at the active band, the activity was significantly more intense in the group irradiated with 280 J/cm2. The present study demonstrated that injury of the sciatic nerve, with consequent muscle denervation, are benefited by the laser therapy, which restores neuromuscular function, active MMP-2 and increases the maximum breaking strength.
authors.affiliation: Department of Biomechanics, Medicine and Rehabilitation of the Locomotor System, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil. rodrigo_andraus@hotmail.com.|Program stricto sensu in Rehabilitation Science, University of Northern Parana - UNOPAR, Rua Marselha 591, Londrina, Paraná, CEP: 86041-140, Brazil. rodrigo_andraus@hotmail.com.
authors.forename: Rodrigo Antonio Carvalho
authors.initials: RAC
authors.lastname: Andraus
authors.affiliation: Graduate Program in Dentistry (GPD - Master's Degree), University of Western São Paulo - UNOESTE, Presidente Prudente, SP, Brazil.
authors.forename: Luciana Prado
authors.initials: LP
authors.lastname: Maia
authors.affiliation: Laboratory of Exercise Physiology, Department of Physiological Sciences, Center of Biological and Health Sciences, Inter Graduate Program in Physiological Sciences, Federal University of São Carlos, São Carlos, SP, Brazil.
authors.forename: Anderson Diogo
authors.initials: AD
authors.lastname: de Souza Lino
authors.affiliation: Program stricto sensu in Rehabilitation Science, University of Northern Parana - UNOPAR, Rua Marselha 591, Londrina, Paraná, CEP: 86041-140, Brazil.
authors.forename: Karen Barron Parron
authors.initials: KBP
authors.lastname: Fernandes
authors.affiliation: Program stricto sensu in Rehabilitation Science, University of Northern Parana - UNOPAR, Rua Marselha 591, Londrina, Paraná, CEP: 86041-140, Brazil.
authors.forename: Marcos Vinícius
authors.initials: MV
authors.lastname: de Matos Gomes
authors.affiliation: Department of Biomechanics, Medicine and Rehabilitation of the Locomotor System, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Rinaldo Roberto
authors.initials: RR
authors.lastname: de Jesus Guirro
authors.affiliation: Department of Biomechanics, Medicine and Rehabilitation of the Locomotor System, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Cláudio Henrique
authors.initials: CH
authors.lastname: Barbieri
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena / Q000528:radiation effects; D005684:Gait; D028022:Low-Level Light Therapy; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000503:physiopathology* / Q000528:radiation effects*; D009416:Nerve Regeneration / Q000528:radiation effects*; D017208:Rats, Wistar; D012584:Sciatic Nerve / Q000293:injuries / Q000503:physiopathology*
chemical_list: D020778:Matrix Metalloproteinase 2
keywords: Denervated muscle; Functional gait analysis; Laser therapy; Metalloproteinase-2; Muscle mechanical resistance; Sciatic functional index