Photobiomodulation ameliorates inflammatory parameters in fibroblast-like synoviocytes and experimental animal models of rheumatoid arthritis

Ryu JH, Park J, Kim BY, Kim Y, Kim NG, Shin YI · Frontiers in Immunology

In the patient-derived synoviocytes, the light reduced the TNF-alpha-induced increase in proliferation, migration and invasion, and downregulated NF-kappa-B activation and the NLRP3 inflammasome. In the mice it inhibited the induction and development of arthritis, with less synovial inflammation and less cartilage degradation, lower serum pro-inflammatory cytokines and higher anti-inflammatory ones, and suppressed NF-kappa-B translocation and NLRP3 activation in the ankle. Light plus methotrexate outperformed either alone, which the authors read as synergy.

Population

Fibroblast-like synoviocytes from rheumatoid arthritis patients, and male DBA/1J mice with collagen-induced arthritis

Intervention

LED at 610 nm for 20 minutes at 5 and 10 mW/cm2 in cells; in mice, 10 mW/cm2 to the ankle joint by direct skin contact for 40 minutes daily for 2 weeks, alone and with methotrexate

Comparator

Unirradiated cells and untreated arthritic mice; methotrexate alone

Limitations

Rheumatoid arthritis, not osteoarthritis. Collagen-induced arthritis is an autoimmune model in which cartilage degradation is driven by systemic inflammation, so a result here says nothing about a mechanical cartilage defect. The wavelength is 610 nm — visible red, shorter than the near-infrared band the cartilage work uses — and it was delivered to a mouse ankle by skin contact, a depth a human knee does not reproduce. Funding was the Korean National Research Foundation, but the LED devices were provided by the Medical Research Center of Color Seven, which is the affiliation of one of the co-authors, while the conflict-of-interest statement declares the research was conducted in the absence of any commercial or financial relationships.