Figure 1.

Hajdu Cheney mice display greater osteoclast number and eroded surface than littermate controls following TNFα treatment. Calvarial bones of Notch2^tm1.1Ecan and sex-matched littermate control mice were administered 2 μg TNFα or PBS (vehicle, Veh) once a day for 4 days over the calvarial vault by subcutaneous injection. A, representative images of histological sections of calvariae stained with TRAP and hematoxylin showing increased number of osteoclasts and eroded surface in TNFα-treated Notch2^tm1.1Ecan mice. The scale bars in the right corner represent 100 μm. B, bone histomorphometric analysis of the calvarial bones from Notch2^tm1.1Ecan (black bars) mutant mice and littermate controls (white bars). Values are means ± S.D.; vehicle n = 4 and TNFα n = 8 biological replicates for control and Notch2^tm1.1Ecan mice, respectively. Parameters shown are as follows: number of osteoclasts/bone perimeter (N.Oc/B.Pm); osteoclast surface/bone surface (Oc.S/BS); eroded surface/bone surface (ES/BS). *, significantly different between TNFα and vehicle, p < 0.05. #, significantly different between Notch2^tm1.1Ecan and control, p < 0.05.