Anti-inflammatory activities of light emitting diode irradiation on collagen-induced arthritis in mice (a secondary publication)

Rheumatoid arthritis (RA) is an auto-immune disease afflicting multiple joints of the body, where as a result of the increase in inflammatory cytokines and tissue destructive factors such as matrix metalloproteinase (MMP)-3, deterioration of the bones and cartilages of the joints occurs. The present investigation was carried out to study the anti-inflammatory activities of light emitting diode (LED) irradiation on hind paw inflammation in collagen-induced arthritis (CIA) mice models.

RA in the CIA mouse model was induced by immunization of DBA/1J mice with intradermal injections of an emulsion of bovine type II collagen and complete Freund's adjuvant. A total of 20 CIA mice were subdivided into the following groups: control group, CIA group and 2 groups of LED irradiated CIA mice (LED groups) (n=5 per group). The mouse knee joint area in the LED groups (the 570 nm and 940 nm groups) was irradiated with LED energy, three times a week for 500 s per session over 8 weeks at a dose of 5 J/cm(2). The hind paw swelling was assessed by the increase in hind paw thickness. The serum levels of the inflammatory cytokines and arthritic factor MMP-3 were determined with an enzyme-linked immunosorbent assay (ELISA).

In the LED-570 and LED-940 groups at 4 weeks after arthritis induction, the swelling inhibition index was 18.1±4.9 and 29.3±4.0 respectively. Interleukin (IL)-1β, IL-6 and MMP-3 serum levels were significantly lower in the LED-940 group.

LED irradiation, particularly in the near-infrared was effective for inhibition of the inflammatory reactions caused by RA.