THE EFFECT OF SODIUM-SALICYLATE ON THE OSTEOCLAST-LIKE CELL-FORMATIONAND BONE-RESORPTION IN A MOUSE BONE-MARROW CULTURE

Salicylates are reported to have an inhibitory effect on bone resorpti on in vivo and in vitro. The present study examined the effect of sodi um salicylate on the formation of osteoclast-like cells in vitro. When mouse bone marrow cells were cultured for 8 days with 10(-8) M 1alpha ,25-dihydroxyvitamin D3 (1alpha,25(OH)2D3), numerous clusters of monon uclear and multinucleated cells (MNCs) formed, which stained positive for tartrate-resistant acid phosphatase (TRAP-positive). In similar cu ltures using sodium salicylate, the number of both TRAP-positive monon uclear and TRAP-positive MNCs were found to diminish in proportion to the concentration of sodium salicylate. A time-course experimental mod el showed that the number of TRAP-positive MNCs decreased slightly whe n sodium salicylate was given early in the culture period, and decreas ed markedly when the drugs were given later in the culture period. Pit formation and bone-resorption area on the bone slices were also inhib ited by adding sodium salicylate continuously with 1alpha,25(OH)2D3. T he sodium salicylate showed no cytotoxic effect because the total numb er of adherent cells, including both TRAP-positive and TRAP-negative c ells, was independent of the presence of sodium salicylate. These resu lts suggest that sodium salicylate has an inhibitory effect on the rec ruitment of osteoclast-like MNCs and that this inhibition is greater d uring the later stage of mouse bone marrow culture.