Figure 4

The effects of several bone resorption inhibitors on human osteoclast and resorption pit morphology. Human osteoclasts were generated as described under Materials and Methods, with or without the presence of bone resorption inhibitors: zoledronic acid (Z.A., 50 nM), selective estrogen receptor modulator (SERM) raloxifene (Ral., 100 nM), non-specific cathepsin K inhibitor E-64 (100 nM), and selective cathepsin K inhibitor AAR494 (AAR, 100 nM). Microphotographs show TRAP-stained cell morphology at culture day 17 (left panels) and pit morphology on dentin (control, zoledronic acid and raloxifene) or bovine bone (E-64 and AAR494). C, control. The activities (IC₅₀ values) of E-64 and AAR494 on cathepsin K, S and L were (E-64: 1.4; 4.1; 2.5 nM, and AAR494: 3.4; 3700; >10000 nM, respectively).