Objective: To compare inhibitory effects of recombinant receptor activator of nuclear factor kappaB protein with bisphosphonate treatment (ALN) on osteoclasts activity and bone loss in ovariectomized mice.
Methods: Twenty-four female KM mice were ovariectomized bilaterally and treated with recombinant receptor activator of nuclear factor kappaB protein, alendronate, or PBS. Twelve weeks later, body weight, biochemical markers of bone metabolism, Micro CT scan and bone morphology were examined.
Results: After 12 weeks administration, the Micro CT scan and bone morphology values of each group were as follow. The control group: BMD (92.600 +/- 14.319) mg/cc, Tb.Th (0.094 +/- 0.011) mm, Tb.Sp (0.455 +/- 0.124) mm, BVF 0.192 +/- 0.023, SMI 1.388 +/- 0.328; the recombinant receptor activator of nuclear factor kappaB protein group: BMD (133.050 +/- 13.022) mg/cc, Tb.Th (0.098 +/- 0.009) mm, Tb.Sp (0.365 +/- 0.105) mm,BVF (0.291 +/- 0.025)%, SMI 0.661 +/- 0.384; the ALN group: BMD(128.013 +/- 16.040) mg/cc, Tb.Th (0.097 +/- 0.011) mm, Tb.Sp (0.376 +/- 0.104) mm, BVF 0.281 +/- 0.024, SMI 0.753 +/- 0.307. In the ovariectomized mice experiments, both recombinant receptor activator of nuclear factor kappaB protein and ALN significantly inhibited ovariectomy-induced bone loss. Compared to the control group (PBS), the recombinant receptor activator of nuclear factor kappaB protein group showed increased distal femur BMD and decreased trabecular spacing (Tb.Sp), whereas the control group had significantly decreased distal femur BMD, significantly decreased Tb.Th, and increased Tb.Sp. There was a significant difference in bone volume fraction among the groups. The TRAP-positive osteoclasts in distal femur bone slices were nearly complete inhibited for Recombinant receptor activator of nuclear factor kappaB protein group and alendronate group.
Conclusion: In vivo, recombinant receptor activator of nuclear factor kappaB protein effectively inhibits the activity of osteoclasts and the resulting bone loss, which has a similar effect as alendronate.