title: Effects of 660 nm low-level laser therapy on muscle healing process after cryolesion.
abstract: The aim of this study was to evaluate the effects of 660 nm low-level laser therapy (LLLT) on muscle regeneration after cryolesion in rat tibialis anterior muscle. Sixty-three Wistar rats were divided into a control group, 10 J/cm(2) laser-treated group, and 50 J/cm(2) laser-treated group. Each group formed three subgroups (n = 7 per group), and the animals were sacrificed 7, 14, or 21 d after lesion. Histopathological findings revealed a lower inflammatory process in the laser-treated groups after 7 d. After 14 d, irradiated animals at both fluences showed higher granulation tissue, new muscle fibers, and organized muscle structure. After 21 d, full tissue repair was observed in all groups. Moreover, irradiated animals at both fluences showed smaller necrosis area in the first experimental period evaluated. MyoD immunoexpression was observed in both treated groups 7 d postinjury. Myogenin immunoexpression was detected after 7 and 14 d. The higher fluence increased the number of blood vessels after 14 and 21 d. These results suggest that LLLT, at both fluences, positively affects injured skeletal muscle in rats, accelerating the muscle-regeneration process.
authors.affiliation: Department of Physiotherapy, Federal University of São Carlos, São Carlos, São Paulo, Brazil.
authors.forename: Natalia C
authors.initials: NC
authors.lastname: Rodrigues
authors.forename: Lívia
authors.initials: L
authors.lastname: Assis
authors.forename: Kelly R
authors.initials: KR
authors.lastname: Fernandes
authors.forename: Angela
authors.initials: A
authors.lastname: Magri
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Ribeiro
authors.forename: Roberta
authors.initials: R
authors.lastname: Brunelli
authors.forename: Daniela C C
authors.initials: DC
authors.lastname: Abreu
authors.forename: Ana Claudia M
authors.initials: AC
authors.lastname: Renno
mesh_terms: D000818:Animals; D003080:Cold Temperature; D006097:Granulation Tissue / Q000473:pathology; D007249:Inflammation / Q000473:pathology; D054023:Lasers, Semiconductor / Q000627:therapeutic use*; D028022:Low-Level Light Therapy; D008297:Male; D018482:Muscle, Skeletal / Q000293:injuries / Q000502:physiology*; D017570:MyoD Protein / Q000032:analysis; D018008:Myogenin / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D014945:Wound Healing / Q000528:radiation effects*
chemical_list: D017570:MyoD Protein; D018008:Myogenin
keywords: MyoD; animal model; cryolesion; gene expression; histopathological analysis; laser therapy; muscle regeneration; muscle tissue; myogenin; rehabilitation