title: Effect of low-level laser therapy on metalloproteinase MMP-2 and MMP-9 production and percentage of collagen types I and III in a papain cartilage injury model.
abstract: Osteoarthritis (OA) resulting from injury or disease is associated with increased levels of several matrix metalloproteinases (MMPs), which degrade all components of the complex extracellular matrix in the cartilage. The objective of this study is to investigate the effect of low-level laser therapy (LLLT) on papain-induced joint damage in rats by histopathology and analysis of metalloproteinase 2 and 9 production. Sixty male Wistar rats were randomly distributed into four groups of 15 animals: (1) non-injury negative control, (2) injury positive control, (3) treated with LLLT at 50 mW, and (4) treated with LLLT at 100 mW. OA was induced in animals using papain (4 % solution) followed by treatment with LLLT. After 7, 14, and 21 days, the animals were euthanized. The articular lavage was collected and centrifuged; then, the supernatant was stored prior to protein analysis by western blot. The material was stained with hematoxylin and eosin for histopathological analysis, and Picrosirius Red was used to estimate the percentage of collagen fibers. To determine normal distribution, ANOVA and Tukey's post hoc test were used for comparison between and within each group at each time period. All data are expressed as mean and standard deviation values, with the null hypothesis considered as p < 0.05. Both laser groups (50 and 100 mW) were effective in tissue repair, decreasing collagen type III expression and increasing type I expression in all experimental periods; however, LLLT at 50 mW reduced metalloproteinase 9 more than at 100 mW in 21 days. LLLT at 50 mW was more efficient in the modulation of matrix MMPs and tissue repair.
authors.affiliation: Postgraduate Program in Rehabilitation Sciences, Universidade Nove de Julho (UNINOVE), São Paulo, São Paulo, Brazil.
authors.forename: Ana Carolina Araruna
authors.initials: AC
authors.lastname: Alves
authors.forename: Regiane
authors.initials: R
authors.lastname: Albertini
authors.forename: Solange Almeida
authors.initials: SA
authors.lastname: dos Santos
authors.forename: Ernesto Cesar Pinto
authors.initials: EC
authors.lastname: Leal-Junior
authors.forename: Eduardo
authors.initials: E
authors.lastname: Santana
authors.forename: Andrey Jorge
authors.initials: AJ
authors.lastname: Serra
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Silva
authors.forename: Paulo de Tarso Camillo
authors.initials: Pde T
authors.lastname: de Carvalho
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002358:Cartilage, Articular / Q000293:injuries / Q000503:physiopathology / Q000528:radiation effects*; D024042:Collagen Type I / Q000378:metabolism; D024061:Collagen Type III / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism / Q000528:radiation effects; D054023:Lasers, Semiconductor / Q000627:therapeutic use*; D028022:Low-Level Light Therapy; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D010206:Papain; D051381:Rats; D017208:Rats, Wistar; D014945:Wound Healing / Q000528:radiation effects*
chemical_list: D024042:Collagen Type I; D024061:Collagen Type III; D010206:Papain; D020778:Matrix Metalloproteinase 2; C522363:Mmp2 protein, rat; D020780:Matrix Metalloproteinase 9; C572337:Mmp9 protein, rat