Abstract: Abstract: 【OBJECTIVE】To study the effect of different concentration of OPG on osteoclasts. 【METHOD】Osteoclasts were obtained by a co-culture system with rat spleen cells and osteoblasts, and supplemented with 5, 10, 25, 50 or 75 ng/ml of OPG respectively. The formation and activation of osteoclasts were ditected by ways of morphologic observation, histochemical staining for tartrate-resistant acid phosphatase (TRAP) and detection of lacunar resorption through scanning electron micrograph. 【RESULTS】Compared with the control group, the number of TRAP positive osteoclasts in experiment group decreased very significantly (P＜0.01). The number and area of lacunar resorption decreased with concentration increasing of OPG, withing the decreasing of OPG. Lacunar resorption wasn’t detected in the group, witch with more than 50 ng/ml OPG. 【CONCLUSION】The resorption activity of osteoclasts is inhibited by inducing osteoclasts formation and activation under OPG.

Key words: osteoclast, osteoprotegerin, tartrate-resistant acid phosphatase, lacunar resorption