Effects of photobiomodulation in pain and articular degeneration in mice arthritis model

ABSTRACT BACKGROUND AND OBJECTIVES: Rheumatoid arthritis is a set of symmetrical inflammatory processes that affects the joints. Currently, drug therapy is the first choice for the treatment of the disease, however it can cause serious side effects. In this context, photobiomodulation appears as a potential resource for treatment. Therefore, the aim of the study was to analyze the effects of low intensity laser treatment on pain and joint degeneration in the arthritis model in mice. METHODS: 24 mice were randomly divided into 4 groups with 6 animals each: SG, ZG, LG and DG. Zymosan was used to induce arthritis. The hyperalgesia was measured using the Von frey test. For the histological analysis, talocrural region samples were collected. Low intensity AsGa Laser equipment was used for the treatment, operating in 904 ηm wavelength, F:1000 Hz, W:50 mW and dose of 1 J/cm2. RESULTS: There was a significant difference (p<0.05) in all times of evaluation in hyperalgesia for the SG group compared with the ZG group, presenting an altered pain threshold. In the histological evaluation, the application of the laser (1 J/cm2) to the arthritic joint reduced the analyzed scores (1.20 ± 0.20) and showed a statistical difference when compared to the ZG group (LG=1.20 ± 0.20; ZG=3.80 ± 0.20, p<0.05). CONCLUSION The low intensity laser with the parameters described in the study was effective in reducing pain and promoting a protective effect on cartilage.