Fig. 4

Apex1 silencing impairs fracture healing progression. Histological analysis at 10-dpf (a), 14-dpf (b), and 21-dpf (c). SO/FG, Safranin O/Fast green. TRAP, tartrate resistant acid phosphatase staining. Left panels, whole callus view; middle left panels, cartilage view; middle right panels, cartilage-bone interphase; right panels, TRAP staining of the cartilage bone interphase. Scale bar, left panel, 1 mm; middle and right panels, 100 μm. Arrowheads show the presence of TRAP⁺ cells. d Histomorphometric quantification of the cartilage area at 10-dpf (WT, n = 6; P-Apex1^KO, n = 5), 14-dpf (WT, n = 15; P-Apex1^KO, n = 10), and 21-dpf (WT, n = 8; P-Apex1^KO, n = 8). Percentage/%, cartilage area/total callus area x 100. Results are expressed as median and interquartile range; whiskers represent maximum and minimum values. P values were determined by one way ANOVA (P < 0.000 1) followed by a Sidàk’s multiple comparisons test. e Histomorphometric quantification of TRAP activity at 10-dpf (WT, n = 6; P-Apex1^KO, n = 5), 14-dpf (WT, n = 18; P-Apex1^KO, n = 11), and 21-dpf (WT, n = 9; P-Apex1^KO, n = 7). Percentage/%, TRAP positive area/Total callus area x 100. Results are expressed as median and interquartile range; whiskers represent maximum and minimum values. P values were determined by one way ANOVA (P = 0.000 2) and Sidàk’s multiple comparisons test