To observe the influence of technetium 99Tc methylenediphosphonate (99Tc-MDP) on osteoclastogenesis induced by receptor activator of NF-kappaB ligand (RANKL) and macrophage-colony stimulating factor (M-CSF) in peripheral blood mononuclear cells in patients with rheumatoid arthritis, and to study the mechanism of 99Tc-MDP in osteoclast differentiation.
The monocytes/macrophages were isolated from peripheral blood in patients with rheumatoid arthritis, incubated in RPMI-1640 with receptor activator of NF-kappaB ligand (RANKL, 25 microg/L), macrophage-colony stimulating factor (M-CSF, 25 microg/L) and different concentrations of 99Tc-MDP (5, 10, 20 and 50 mg/L) for 4, 12, and 20 days. Tartrate resistant acid phosphatase staining was used to observe the formation of osteoclasts.
After 12 or 16 days culture of peripheral blood mononuclear cells, plenty of large multinuclear cells could be found on the coverslips. 99Tc-MDP markedly inhibited those changes and the inhibitory effects were increased as the concentration of 99Tc-MDP increased (P<0.05).
99Tc-MDP probably has some protective effect on rheumatoid arthritis by inhibiting osteoclast formation.