Fig. 1

Repeated amputations inhibit digit tip regeneration. A Quantification of terminal phalanx (P3) bone volume and B P3 bone length normalized to the amputated bone volume (1 DPA) after each amputation. Asterisks indicate differences between amputated and regenerated digits for each regeneration cycle unless a bar is used to denote a specific comparison. A, B Black dashed lines indicate when digit tip amputation occurred. n = 40 digits; Differences were determined using a mixed-effects model with matching analysis test and a Tukey’s multiple comparisons test. Data are presented as mean ± SD; * = p < 0.05; *** = p < 0.001; **** = p < 0.0001; n.s. = not significant. C 3D µCT renderings of unamputated and regenerated P3 bones 28 days following amputation. A sample of 5 digits, longitudinally imaged during the experiment (same digit repeatedly imaged in each row) is presented to demonstrate variation