Figure 4. Osteopetrosis in Clcn7^td/td mice.

A Micro-CT revealed similar osteopetrosis of tibiae of 3-week-old Clcn7^−/− and Clcn7^td/td mice (scale bar: 1 mm).

B Micro-CT image of skull from P22 Clcn7^td/td mouse showed impaired tooth eruption (scale bar: 10 mm).

C Similarly, increased bone volume fraction of proximal tibia metaphyseal trabecular bone in Clcn7^td/td mice and Clcn7^−/− mice. BV, bone volume; TV, tissue volume. Student’s t-test was applied; n.s., not significant. Error bars denote s.e.m.

D Electron microscopy showed mature, immature and lacking ruffled borders of Clcn7^td/td osteoclasts despite the presence of a sealing zone (SZ). Arrows point at ruffled borders (scale bar: 5 μm) (Bo = bone; N = nucleus).

E Percentage of WT, Clcn7^unc/unc, Clcn7^td/td, Clcn7^−/− osteoclasts exhibiting absent, immature or mature ruffled borders. Error bars denote s.e.m.