title: Infrared (810 nm) low-level laser therapy in rat achilles tendinitis: a consistent alternative to drugs.
abstract: Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used and can reduce musculoskeletal pain in spite of the cost of adverse reactions like gastrointestinal ulcers or cardiovascular events. The current study investigates if a safer treatment such as low-level laser therapy (LLLT) could reduce tendinitis inflammation, and whether a possible pathway could be through inhibition of either of the two-cyclooxygenase (COX) isoforms in inflammation. Wistar rats (six animals per group) were injected with saline (control) or collagenase in their Achilles tendons. Then, we treated them with three different doses of IR LLLT (810 nm; 100 mW; 10 s, 30 s and 60 s; 3.57 W cm(-2); 1 J, 3 J, 6 J) at the sites of the injections, or intramuscular diclofenac, a nonselective COX inhibitor/NSAID. We found that LLLT dose of 3 J significantly reduced inflammation through less COX-2-derived gene expression and PGE(2) production, and less edema formation compared to nonirradiated controls. Diclofenac controls exhibited significantly lower PGE(2) cytokine levels at 6 h than collagenase control, but COX isoform 1-derived gene expression and cytokine PGE(2) levels were not affected by treatments. As LLLT seems to act on inflammation through a selective inhibition of the COX-2 isoform in collagenase-induced tendinitis, LLLT may have potential to become a new and safer nondrug alternative to coxibs.
authors.affiliation: Laboratory of Pharmacology and Experimental Therapeutics, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP-Brazil.
authors.forename: Rodrigo Labat
authors.initials: RL
authors.lastname: Marcos
authors.forename: Ernesto Cesar Pinto
authors.initials: EC
authors.lastname: Leal Junior
authors.forename: Felipe de Moura
authors.initials: Fde M
authors.lastname: Messias
authors.forename: Maria Helena Catelli
authors.initials: MH
authors.lastname: de Carvalho
authors.forename: Rodney Capp
authors.initials: RC
authors.lastname: Pallotta
authors.forename: Lúcio
authors.initials: L
authors.lastname: Frigo
authors.forename: Rosângela Aparecida
authors.initials: RA
authors.lastname: dos Santos
authors.forename: Luciano
authors.initials: L
authors.lastname: Ramos
authors.forename: Simone
authors.initials: S
authors.lastname: Teixeira
authors.forename: Jan Magnus
authors.initials: JM
authors.lastname: Bjordal
authors.forename: Rodrigo Álvaro Brandão
authors.initials: RÁ
authors.lastname: Lopes-Martins
mesh_terms: D000125:Achilles Tendon / Q000293:injuries*; D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D007259:Infrared Rays; D053685:Laser Therapy; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction; D052256:Tendinopathy / Q000601:surgery*
chemical_list: D017931:DNA Primers