Abstract: ObjectiveTo investigate the effects of infrared radiation and magnetic fields on the synovitis of rabbit with experimental knee osteoarthritis (OA).MethodsTwenty-four New Zealand grown rabbits were duplicated for OA model of the knee by extended fixation technique, and after 6 weeks, all rabbits were unchained from fixation. The rabbits were randomly divided into four groups: control group (no treatment), infrared group (treated with infrared radiation ), magnet-therapy group (treated with magnetic fields ) and the combined therapy group (treated with infrared radiation and magnetic fields). At the ends of the first, second and third week after treatment, 2 rabbits in each group were taken to measure the general change and histopathology of their synovium.ResultsCompared with other groups, the severity of synovitis (include the synovium line cells proliferation, the invading of granulation and blood vessels in the underlayer of synovium, the infiltration of inflammatory cells) declined significantly in combined therapy group. Scores of Ayral's index of combined group were significantly lower than other groups ( P<0.05), and there was no significant difference between infrared group and magnet-therapy group ( P>0.05).ConclusionThe combination of infrared radiation and magnetic fields can efficiently suppress the synovitis of OA and alleviate the tissue's destructions.

Key words: osteoarthritis, infrared radiation, magnetic fields, histopathology, synovitis