Abstract: Objective To study the expression of interleukin-1β (IL-1β) in synovia and synovium of rats after high intensity exercise.Methods 24 healthy male Sprague-Dawley rats were randomly divided into control group and high intensity group, and the latter were forced to run 60 min at the speed of 28 m/min for 6 weeks. The histological changes of cartilage from the lesion areas of medial femoral condyle and synovium of knee joint were examined with HE stain and the expression of IL-1β in synovium with immunohistochemistry, in synovial fluid with the enzyme-linked immunosorbent assay (ELISA). Results The articular cartilage of knee were injured and synovitis were found in high intensity group. The expression of IL-1β both in synovial fluid and in synovium of the knee were more in high intensity group than in control group (P<0.05). Conclusion High intensity exercise could cause aticular cartilage injury, synovitis and over expression of IL-1β in synovia and synovium, which may associated with post-traumatic osteoarthritis.

Key words: exercise, interleukin-1β, osteoarthritis, synovium, synovia