RESUMEN
Objective: To evaluate the effects of photobiomodulation (PBM) therapy on oxidative stress and histological aspects of knee osteoarthritis (OA) induced by sodium monoiodoacetate in Wistar rats. Background: OA is a chronic degenerative disease. In addition to the inflammatory role, other factors, such as redox balance, appear to contribute to changes in the articular cartilage, the main articular structure affected. PBM therapy using light-emitting diode (LED) has been proposed to treat the disease by favoring anti-inflammatory effects and modulating markers of oxidative stress, acting on the degenerative process of cartilage. Methods: Twenty-seven male rats were separated into three groups: control (CG), OA (OAG), and LED treatment (LEDG). In the LED group, PBM (LED 630 nm, 300 mW, 9 J/cm2, 0.3 W/cm2, 30 sec) was applied, starting 24 h after induction, three times per week, for 8 weeks. Cartilage thickness, number of chondrocytes, enzymatic antioxidant defenses [superoxide dismutase (SOD) and catalase (CAT)], oxidative damage [thiobarbituric acid reactive substances (TBARS)], and nonenzymatic defense (ferric reducing antioxidant power) were analyzed. Results: The LEDG had higher average cartilage thickness compared with the OAG and had similar thickness to the CG. Also, the number of chondrocytes was similar to the CG. In the oxidative stress analysis, the LEDG presented antioxidant enzymatic activity (SOD and CAT) higher than the CG, and presented concentration of TBARS lower than the CG and OAG groups. Conclusions: PBM therapy was effective in recovering oxidative stress and preserving the articular cartilage aspects in a knee OA animal model.