Ana O. Hoff, Philip Catala-Lehnen, Pamela M. Thomas, Matthias Priemel, Johannes M. Rueger, Igor Nasonkin, Allan Bradley, Mark R. Hughes, Nelson Ordonez, Gilbert J. Cote, Michael Amling, Robert F. Gagel
Comparison of bone resorption and formation in female WT and KO animals. (a) Parameters of bone resorption. Histomorphometric analysis of osteoclast number per mm bone perimeter (Noc/BPm) and urinary DPD crosslinks (a marker of bone resorption) was performed in 1- and 3-month-old WT (gray bars) and KO (black bars) mice. (b) Parameters of bone formation. Histomorphometric analysis of osteoblast number per mm bone perimeter (Nob/BPm) (left graph) and in vivo analysis of bone formation (right graph) in 1- and 3-month-old WT and KO mice. The rate of bone formation was determined by in vivo dual calcein labeling; the graphs provide quantification of the bone formation rate per bone surface (BFR/BS). (c) Representative fluorescent micrographs demonstrate the two labeled mineralization fronts, with the arrows indicating growth between labelings. Note the greater distance between the two labeled areas in the KO mice than in the WT animals. All experiments included five animals per group; bars represent mean ± SD. *Statistically significant difference between WT and KO mice (P < 0.05).