Treatment with anti-sclerostin antibody prevents 5TGM1 myeloma-induced suppression of bone formation. (A) Tartrate-resistant acid phosphatase (TRAP)/hematoxylin-stained histologic sections from representative mice from each treatment group showing osteoblasts on the endocortical bone surface (inset, blue arrows) and osteoclasts reacted for TRAP and stained red (white arrows); scale bar represents 200 µm. Slides were scanned on a Scanscope CS2 (Aperio) up to original magnification ×40, and images were captured by using an Aperio Imagescope at digital magnification ×20. (B) Dot plots of osteoclast surface/bone surface (Oc.S/BS) and number of osteoclasts/bone surface (N.Oc/BS) (data are mean ± 1 SEM; *P < .05; **P < .001). (C) Dot plots of osteoblast surface/bone surface (Ob.S/BS) and number of osteoblasts/bone surface (N.Ob/BS) (n = 8) (data are mean ± 1 SEM; *P < .05; **P < .001). (D) Representative sections from each group showing mineralized bone surfaces labeled with calcein. Images were captured on a Leica DMI 5500 at ×2.5 by using LAS X software (Leica); scale bar represents 500 µm. Double-label bone surfaces were used to measure mineral apposition rate (inset: red arrows show the distance between 2 labels separated by a fixed time interval). Images were captured on a Leica DMI 5500 at ×40 using LAS X software (Leica). Scale bar represents 20 µm. (E) Dot plots of MAR, mineralizing surface (MS), and BFR (n = 5; data are mean ± 1 SEM; *P < .05; **P < .01; #P < .05 (Student t test); ##P < .01 (Student t test). ES, endosteal bone surface; PS, periosteal bone surface.