Effects of recombinant human IL-I? on production of prostaglandin E2, leukotriene B4, NAG, and superoxide by human synovial cells and chondrocytes

Abstract

The effects of recombinant human IL-1β on the production of prostaglandin E₂ (PGE₂), leukotriene B₄ (LTB₄),N-acetyl-β-D-glucosaminidase (NAG), and superoxide by synovial cells and chondrocytes derived from osteoarthritis patients were determined. IL-1β markedly enhanced PGE₂ production in chondrocytes and, to the lesser extent, in synovial cells. Synovial cells and chondrocytes spontaneously released LTB₄ into culture medium and IL-1β significantly inhibited LTB₄ production by these cells. IL-1β significantly suppressed the release of NAG and superoxide by synovial cells, whereas it significantly enhanced the production of NAG and superoxide by chondrocytes. Production of intracellular superoxide dismutase by synovial cells was significantly enhanced on incubation with IL-1β, but that of chondrocytes was not altered. IL-6, unlike IL-1β, significantly suppressed the production of NAG and superoxide by synovial cells and chondrocytes. These results suggest that IL-1 has differing effects on the release of mediators by synovial cells and chondrocytes and that these cells also vary in their responses to IL-1β and IL-6.