title: Effect of laser therapy on skeletal muscle repair process in diabetic rats.
abstract: Skeletal muscle myopathy is a common source of disability in diabetic patients. This study evaluated whether low-level laser therapy (LLLT) influences the healing morphology of injured skeletal muscle. Sixty-five male Wistar rats were divided as follows: (1) sham; (2) control; (3) diabetic; (4) diabetic sham; (5) nondiabetic cryoinjured submitted to LLLT (LLLT); (6) diabetic cryoinjured submitted to LLLT (D-LLLT); and (7) diabetic cryoinjured non-treated (D). Diabetes was induced with streptozotocin. Anterior tibialis muscle was cryoinjured and received LLLT daily (780 nm, 5 J/cm(2), 10 s per point; 0.2 J; total treatment, 1.6 J). Euthanasia occurred on day 1 in groups 1, 2, 3, and 4 and on days 1, 7, and 14 in groups 5, 6, and 7. Muscle samples were processed for H&E and Picrosirius Red and photographed. Leukocytes, myonecrosis, fibrosis, and immature fibers were manually quantified using the ImageJ software. On day 1, all cryoinjured groups were in the inflammatory phase. The D group exhibited more myonecrosis than LLLT group (p < 0.05). On day 14, the LLLT group was in the remodeling phase; the D group was still in the proliferative phase, with fibrosis, chronic inflammation, and granulation tissue; and the D-LLLT group was in an intermediary state in relation to the two previous groups. Under polarized light, on day 14, the LLLT and D-LLLT groups had organized collagen bundles in the perimysium, whereas the diabetic groups exhibited fibrosis. LLLT can have a positive effect on the morphology of skeletal muscle during the tissue repair process by enhancing the reorganization of myofibers and the perimysium, reducing fibrosis.
authors.affiliation: Postgraduate Program in Biophotonics Applied to Health Sciences, Universidade Nove de Julho, São Paulo, São Paulo, Brazil, 01504-001. cristiane321@gmail.com
authors.forename: Cristiane Miranda
authors.initials: CM
authors.lastname: França
authors.forename: Cristiano
authors.initials: C
authors.lastname: de Loura Santana
authors.forename: Camila Borin
authors.initials: CB
authors.lastname: Takahashi
authors.forename: Agnelo Neves
authors.initials: AN
authors.lastname: Alves
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: De Souza Mernick
authors.forename: Kristianne Porta Santos
authors.initials: KP
authors.lastname: Fernandes
authors.forename: Daniela
authors.initials: D
authors.lastname: de Fátima Teixeira da Silva
authors.forename: Sandra Kalil
authors.initials: SK
authors.lastname: Bussadori
authors.forename: Raquel Agnelli
authors.initials: RA
authors.lastname: Mesquita-Ferrari
mesh_terms: D000818:Animals; D003094:Collagen / Q000378:metabolism; D048909:Diabetes Complications / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy*; D003921:Diabetes Mellitus, Experimental / Q000150:complications / Q000378:metabolism / Q000473:pathology; D004195:Disease Models, Animal; D006801:Humans; D028022:Low-Level Light Therapy; D008297:Male; D018482:Muscle, Skeletal / Q000293:injuries* / Q000473:pathology / Q000528:radiation effects*; D009135:Muscular Diseases / Q000150:complications* / Q000473:pathology / Q000532:radiotherapy*; D051381:Rats; D017208:Rats, Wistar; D012038:Regeneration / Q000502:physiology / Q000528:radiation effects; D014945:Wound Healing / Q000502:physiology / Q000528:radiation effects*
chemical_list: D003094:Collagen