title: Comparative analysis of two low-level laser doses on the expression of inflammatory mediators and on neutrophils and macrophages in acute joint inflammation.
abstract: Synovial membrane inflammation plays an important role in osteoarthritis (OA) pathophysiology. The synovial tissue of patients with initial OA is characterized by mononuclear cell infiltration and the production of pro-inflammatory cytokines and other mediators of joint injury. The study aims to evaluate the effect of low-level laser therapy (LLLT) at doses of 2 and 4 J on joint inflammation in rats induced by papain through histopathological analysis, differential counts of inflammatory cells; gene expression of IL-1β, IL-6, and IL-10; and TNF-α protein expression. Male Wistar rats (20) were randomly divided (5 animals each) into a negative control group, an inflammation injury positive control group, a 2-J LLLT group subjected to injury and treated with 2 J of LLLT, and a 4-J LLLT group subjected to injury and treated with 4 J of LLLT. The animals were subjected to joint inflammation (4 % papain solution) and treated with LLLT. On the day of euthanasia, articular lavage was collected and centrifuged. The supernatant was analyzed for TNF-α protein expression by ELISA and IL-1β, IL-6, and IL-10 mRNA by RT-PCR. The joint tissue was also examined histologically. ANOVA with Tukey's post hoc test was used for comparisons. All data were expressed as means ± S.D. (p < 0.05). Both laser modalities were efficient in reducing cellular inflammation and decreasing the expression of IL-1β and IL-6. However, the 2-J treatment led to more reduction in TNF-α than the 4-J treatment. A single application of LLLT with 2 J was more efficient in modulating inflammatory mediators and inflammatory cells.
authors.affiliation: Department of Physical Therapy, Universidade Nove de Julho (UNINOVE), São Paulo, São Paulo, Brazil.
authors.forename: Solange Almeida
authors.initials: SA
authors.lastname: dos Santos
authors.forename: Ana Carolina Araruna
authors.initials: AC
authors.lastname: Alves
authors.forename: Ernesto Cesar Pinto
authors.initials: EC
authors.lastname: Leal-Junior
authors.forename: Regiane
authors.initials: R
authors.lastname: Albertini
authors.forename: Rodolfo de Paula
authors.initials: RP
authors.lastname: Vieira
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Ligeiro
authors.forename: Jose Antonio Silva
authors.initials: JA
authors.lastname: Junior
authors.forename: Paulo de Tarso Camillo
authors.initials: Pde T
authors.lastname: de Carvalho
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000276:immunology / Q000378:metabolism / Q000528:radiation effects*; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D018836:Inflammation Mediators / Q000378:metabolism; D054023:Lasers, Semiconductor / Q000627:therapeutic use*; D007958:Leukocyte Count; D028022:Low-Level Light Therapy; D008264:Macrophages / Q000276:immunology / Q000528:radiation effects*; D008297:Male; D009504:Neutrophils / Q000276:immunology / Q000528:radiation effects*; D020370:Osteoarthritis, Knee / Q000276:immunology / Q000532:radiotherapy*; D017208:Rats, Wistar
chemical_list: D016207:Cytokines; D018836:Inflammation Mediators