Abstract
In order to investigate the therapeutic effect of high molecular weight hyaluronate (HA) on rheumatoid arthritis (RA), HA was injected into the proximal interphalangeal (PIP) joints of monkeys with collagen-induced arthritis, an experimental model of the disease. An immunohistochemical study was then performed using antibodies against collagen, interleukin1 (IL-1), tumor necrosis factor (TNF), and stromelysin. Intra-articular injection of HA at an early stage of arthritis inhibited the production of cytokines by chondrocytes and synovial cells, and also prevented the degeneration of articular cartilage and the proliferation of synovial tissue. In addition, the appearance of osteoclasts in the subchondral bone was suppressed by HA injection. Even in the advanced stage of arthritis, the hyaline cartilage matrix was relatively well preserved in animals treated with HA. These findings suggest that HA could prevent the progression of articular destruction by inhibiting the inflammatory response of articular cartilage, synovial tissue, and subchondral bone. Although the mechanism of this anti-inflammatory effect of HA is still unclear, it is implied that the intra-articular injection of HA into the affected joints of RA patients may improve their arthritis.
