INHIBITORY EFFECTS OF TRK-530 ON RAT ADJUVANT ARTHRITIS

TRK-530 is a novel bisphosphonate derivative. We examined the anti-inf lammatory effects of TRK-530 on adjuvant arthritis (AA) rats. When TRK -530 at a dose of 2.5 mg/kg was administered for 2 weeks to AA rats, i t inhibited destructive changes in arthritic joints such as paw edema, bone loss and joint degeneration. TRK-530 also inhibited splenomegaly and suppressed the increase in serum sialic acid which is measured as a systemic parameter of inflammation. To clarify the inhibitory mecha nism of TRK-530, interleukin-1 (IL-1)-like activities of resident peri toneal macrophages in AA rats given TRK-530 were compared with those o f control rats. We found that TRK-530 inhibited IL-1-like activity ind uced by bacterial lipopolysaccharide 6 weeks after administration when the IL-1-like activities of control rats were still at high levels, T hese findings suggest that TRK-530 exerts anti-inflammatory activities in AA rats.