Objective To observe the effect of recombinant human osteoprotegerin (rhOPG) on osteoclasts which were stimulated by polyethylene particles and to investigate the feasibil ity of applying rhOPG for the prosthetic aseptic looseness. Methods The osteoclasts were isolated from the long bones of 5 New Zealand rabbits born within 24 hours, weighing 80-100 g, male or female, and were plated into the 24-well coversl ips (10 mm × 10 mm) and bone sl ices (8 mm × 8 mm × 50 μm) at the density of 1 × 105/mL. Based on the different concentration and density of rhOPG and polyethylene particles, the plates of culture were divided into 3 groups: the group with polyethylene particles of 1 × 109/mL (polyethylene group), the group co-cultured with polyethylene particles of 1 × 109/mL and rhOPG of 100 ng/mL (polyethylene/rhOPG group) and the control group . The glass cover sl ips and bone sl ices were exposed to HE, toluidine blue and tartrate-resistant acid phosphatase (TRAP) staining at 1, 3, 5 and 7 days, and TRAP positive multinucleated cells and bone resorption tips were counted. Scanning electron microscope was used to observe the pits of bone resorption. Results The osteoclast was rose-red when exposed to TRAP staining. For the number of the TRAP-positive osteoclasts, the polyethylene group witnessed an obviouse increase compared with the control group and the polyethylene/rhOPG group after 5 and 7 days of culture (P lt; 0.05). And no significant difference between the control group and the polyethylene/rhOPG group was evident (P gt; 0.05). The pits of bone resorption was blue-purple when exposed to toluidine blue staining. For the number of bone resorption pits in the bone sl ice, significant difference was evident between the polyethylene group and the control group after 5 and 7 days of culture (P lt; 0.05), and there was significant different between the polyethylene/rhOPG group and the polyethylene group 1, 3, 5 and 7 days after culture (P lt; 0.05). Conclusion rhOPG could inhibit the stimulated effect of polyethylene particles on osteoclasts, and might be used to prevent the prosthetic aseptic looseness after artificial joint substitution.