Negative Regulation of Bone Formation by the Transmembrane Wnt Antagonist Kremen-2
Figure 6
Impaired bone formation in Col1a1-Krm2 transgenic mice.
(A) Toluidine blue staining of non-decalcified vertebral body sections from 6 weeks old female wildtype and Col1a1-Krm2 transgenic littermates revealing that the normal appearance of cuboidal osteoblasts (arrows) covering trabecular bone surfaces is only observed in wildtype controls (scale bars, 50 µm). (B) Histomorphometric quantification showing that the number of osteoblasts (ObN/BPm, osteoblast number per bone perimeter) is not significantly decreased in sections from transgenic mice. (C) Fluorescent micrographs showing that overall calcein labeling is reduced in vertebral bodies of 6 weeks old female Col1a1-Krm2 transgenic mice (top, scale bars, 1 mm), as is the distance between the labeled surfaces at endosteal bone surfaces of the tibia (bottom, scale bars, 20 µm). (D) Histomorphometric quantification of the bone formation rate (BFR/BS, bone formation rate per bone surface) in female wildtype and Col1a1-Krm2 transgenic littermates. (E) Northern Blot expression analysis for Col1a1, Bglap and Ibsp using femur RNA of 6 weeks old female wildtype and transgenic mice. (F) Serum levels of osteocalcin and activities of alkaline phosphatase in 6 weeks old female wildtype and transgenic mice. All bars represent mean ± SD (n = 6). Asterisks indicate statistically significant differences.