Effectiveness of photobiomodulation therapy and aerobic exercise training on articular cartilage in an experimental model of osteoarthritis in rats

Osteoarthritis (OA) is the most common disease of the knee joints in adults throughout the world. Photobiomodulation (PBM) and physical exercise have been studied for clinical treatment of OA, even though the effects and action mechanisms have not yet been clarified. The aim of this study was to evaluate the effects of PBM and aerobic exercise (associated or not) on degenerative modifications and inflammatory mediators in articular cartilage using an experimental model of knee OA. Forty male Wistar rats were randomly divided into 4 groups: OA animals without treatment (OAC); OA plus aerobic exercise training (OAT); OA animals plus PBM treatment (OAP); OA plus aerobic exercise training and PBM treatment (OATP). The exercise training (treadmill; 16m/min; 50 min/day) and the PBM treatment started 4 weeks after the surgery, 3 days/week for 8 weeks. The results showed that all treated groups showed a lower degenerative process measured by OARSI system and higher thickness values. Moreover, aerobic exercise and PBM (associated or not) decreased iNOS expression and increased IL-10 expression in OAT and OATL compared to OAC. Furthermore, a lower TGF-β expression was observed in associated therapies. These results suggest that PBM and aerobic exercise training were effective in modulating inflammatory process and preventing cartilage degeneration in knees in OA rats.