Effects of phototherapy on cartilage structure and inflammatory markers in an experimental model of osteoarthritis

The aim of this study was to evaluate the effects of laser phototherapy on the degenerative modifications on the articular cartilage after the anterior cruciate ligament transection (ACLT) in the knee of rats. Eighty male rats (Wistar) were distributed into four groups: intact control group (IG), injured control group (CG), injured laser treated group at 10 J/cm(2) (L10), and injured laser treated group at 50 J/cm(2) (L50). Animals were distributed into two subgroups, sacrificed in 5 and 8 weeks postsurgery. the ACLT was used to induce knee osteoarthritis in rats. After 2 weeks postsurgery, laser phototherapy initiated and it was performed for 15 and 30 sessions. the histological findings revealed that laser irradiation, especially at 10 J/cm(2), modulated the progression of the degenerative process, showing a better cartilage structure and lower number of condrocytes compared to the other groups. Laser phototherapy was not able to decrease the degenerative process measured by Mankin score and prevent the increase of cartilage thickness related to the degenerative process. Moreover, it did not have any effect in the biomodulation of the expression of markers IL1 beta, tumor necrosis factor-alpha, and metalloprotein-13. Furthermore, laser irradiated animals, at 50 J/cm(2) showed a lower amount of collagen type 1. (C) 2013 Society of Photo-Optical Instrumentation Engineers (SPIE)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Univ Fed Sao Carlos, Dept Physiotherapy, BR-13565902 São Paulo, BrazilAdventist Univ Ctr São Paulo, Dept Physiotherapy, BR-05828001 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Morphol & Pathol, BR-13565902 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biosci, BR-11060001 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Morphol & Pathol, BR-13565902 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biosci, BR-11060001 São Paulo, BrazilWeb of Scienc