Effects of Photobiomodulation on Osteoarthritis from In Vivo and In Vitro Studies: A Narrative Review

Osteoarthritis (OA) is an inflammatory disorder characterized by metabolic changes in the bone tissue, including the degeneration of hyaline cartilage (articular cartilage) and fibrocartilage (including the meniscus and labrum), sclerosis of the subchondral bone, and osteophyte formation. OA poses a major challenge for adults of all ages, leading to increased morbidity and decreased quality of life. The current conventional therapies mainly focus on pain control, with no definitive or regenerative therapies to reverse OA progression available. Lasers consist of electromagnetic waves generated by radiation emitted by an excited material. In medicine and dentistry, photobiomodulation by low-power laser therapy (photobiomodulation therapy [PBMT]) has been widely applied clinically to promote healing, regenerate tissue, modulate inflammation, and relieve pain. Basic studies have explored the regulation of OA manifestations and joint inflammation using PBMT, as well as the mechanisms of action involved, and clinical research has validated the beneficial effects of PBMT for patients with OA. However, the effects of PBM on OA and its mechanisms of action remain unknown. Herein, we review basic research that has examined the effects of PBMT on OA using in vitro and in vivo testing and discuss future challenges and prospects.