Skeletally mature Colα1(I) 2.3-Cre;Kif3a^fl/fl mice exhibit less responsiveness to mechanical loading compared to control mice.

(A) Representative images of non-loaded (left) and loaded (right) ulnae of Colα1(I) 2.3-Cre;Kif3a^fl/fl (top) and control (bottom) mice. Fluorochrome labels (Calcein-green and Alizarin Red-red) given on Days 5 and 12 after the onset of mechanical loading. (B to D) Relative mineralizing surface (rMS/BS, %, B), mineral apposition rate (rMAR, µm per day, C), and bone formation rate (rBFR/BS, µm³/µm² per year, D) of mechanically loaded mice. Colα1(I) 2.3-Cre;Kif3a^fl/fl mice exhibited a decrease of 32% in rMAR and 33% in rBFR/BS when compared to control mice. Data presented as mean ± SEM. * p<0.05.