Figure 1. Deletion of Bak and Bax increases femoral bone mass.

(A–E) Experiments with the OCN-Cre deleter strain. (A) Level of Bax genomic DNA in osteocyte-enriched femoral shafts, brain, spleen or liver from 3-month-old female mice; n=5 animals per group; *p <0.05 vs. Bak^ΔBax^f/f. (B) Bax expression (left panel) and caspase-3 activity (right panel) in triplicate cultures of osteoblastic cells established from marrow-derived progenitors of 3-month-old female mice. Caspase-3 activity was determined 8 hours following addition of vehicle (Veh) or 0.2 µM camptothecin (Campt), *p<0.05. Sequential determination of femoral BMD (C) spinal BMD (D), and body weight (E) in a cohort of female mice; n=9–14/group. *p<0.05 vs. littermate controls by random coefficients model. (F–I) Experiments with the Osx1-Cre deleter strain. (A) Level of Bax genomic DNA in osteocyte-enriched femoral shafts from 2-month-old female mice; n=3 animals per group; *p<0.05 vs. Bak^Δ;Bax^f/f. Sequential determination of femoral BMD (G), spinal BMD (H) and body weight (I) in a cohort of female mice; n=6–11/group, *p<0.05 vs. Bak^Δ and BakΔOsx1-Cre littermate controls by random coefficients model.