Effect of WEAO on bone resorbing activity of mature osteoclasts. Mature osteoclasts were seeded on a plate coated with an inorganic crystalline calcium phosphate and then cultured with vehicle or WEAO (20–80 μg/mL) for 24 h. (A) Cells were stained for TRAP activity, and resorption pits formed by osteoclasts were photographed. Scale bar, 200 μm. (B) The number of osteoclasts (Oc) was counted. n.s, not significant. (C) The total area of resorption pits was measured.