FIGURE 13

Restoration of HCS-cells during fin regeneration after amputation. (A–E) Projections of 5-HT-positive cells (as detected by immunofluorescence) on whole mount uninjured fins, at 2 days post-amputation (dpa), 7, 14, and 30 dpa. The formation of the new outgrowth distal to the amputation plane (dashed line) is associated with concomitant restoration of HCS-cells. (A’–E’) Higher magnification of areas in squares in corresponding image. (F) Quantification of overall HCS-cell density at the indicated time points. No significant (ns) difference in density during regeneration compared with uninjured fins (126 ± 67 cells per mm² in uninjured; 102 ± 77 at 2 dpa; 88 ± 39 at 7 dpa; 109 ± 50 at 14 dpa; 84 ± 21 at 30 dpa). N ≥ 7. (G) Quantification of HCS-cell density in primary interray (PI) vs. bifurcation interray (BI) in uninjured fins vs. fin regenerates at 30 dpa, as illustrated in Figure 6C. Differential density is reestablished after regeneration (75 ± 43 vs. 386 ± 291 cells per mm² in uninjured and 40 ± 18 vs. 178 ± 64 at 30 dpa). N ≥ 7. ^∗∗∗p < 0.001.