Fig. 3

Repeated amputation stunts the anabolic phase of digit bone regeneration. A Quantification of normalized bone volume measurements for digits amputated 5 times (5th Amp; n = 32–52 digits) and control digits amputated for the first time (1st Amp 2MO; n = 18–26 digits). B Rates of bone volume changes calculated from (A). Negative values indicate bone degradation rate, positive values bone formation rate. C–J Mallory Trichrome-stained digit sections of 5th Amp digits (upper panel) and 1st Amp sections (lower panel) at wound closure and blastema initiation (C, D, G, H) and bone formation (E, F, I, J). Scale bar indicates 200 µm. Data are presented as mean ± SD and significant differences were determined using an unpaired t test. * = p < 0.05; ** = p < 0.01; *** = p < 0.001; **** = p < 0.0001