Figure 6

Schematic illustration of normal or inhibited osteoclastic resorption. Upper panel: Normal bone resorption with acidification of the resorption lacuna followed by proteolysis for removal of the organic matrix. The resulting pit appearance is shown in the column to the far right. Middle panel: Inhibition of acidification leads to disruption of both organic and inorganic resorption. Only residual pits are formed. Lower panel: Inhibition of cathepsin K will not prevent inorganic resorption, whereas organic resorption is potently inhibited. The resulting pits will be packed with non-dissolved organic matrix, and the pits will have a lower depth than normal pits.