Increased retention of calcified cartilage and bone in response to treatment with CatK inhibitor or ALN. Representative histological images of distal femoral region from rabbits treated with (a, b) vehicle, (c, d) alendronate, and (e, f) a cathepsin K inhibitor for 10 days are shown. Distal femurs (a, c and e) and their metaphysis regions (b, d and f) are shown at 0.5X and 1X, respectively. Bone, blue trabecular spicules; BM, bone marrow; GP, growth plate. Scale bar = 1 mm.