Inhibition of osteoclast-like cell formation by sodium salicylate and indomethacin in mouse bone marrow culture.

The present study examined the effect of sodium salicylate and indomethacin on the recruitment of osteoclast-like cells in vitro. When mouse bone marrow cells were cultured for 8 days with 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25-(OH)2D3, 10(-8) M), prostaglandin E2 (PGE2, 10(-6) M) and recombinant human interleukin-1 alpha (rHIL-1 alpha, 2 ng/ml), numerous tartrate-resistant acid phosphatase (TRAP-positive) multinucleated cells (MNCs) formed. Adding sodium salicylate or indomethacin inhibited the formation of TRAP-positive MNCs in a dose-dependent manner. This inhibitory effect was more pronounced when the drugs were given at a later stage in the culture period. Indomethacin appeared to be more potent than sodium salicylate. PGE2 production was inhibited by sodium salicylate or indomethacin. Exogenous PGE2 failed to overcome the inhibitory effect of both drugs. These results suggest that sodium salicylate and indomethacin have inhibitory effects on the recruitment of osteoclast-like MNCs, preferentially on the later stage, and that PGE2 is not the only compound targeted by these drugs in reducing osteoclast-like cell formation in mouse bone marrow culture.