Fig. 4
Macrophages modulate the proliferative capacity of the regeneration blastema. (A) Hematoxylin-stained sections of tail fin regenerates (blastemal region) at 3 dpa. Macrophage-depleted fins (right) display slightly reduced numbers of deep mesenchymal cells of the blastema. Arrowheads indicate the plane of amputation. (B) Blastemal and macrophage proliferation assessed by staining 2 (iii,iv) or 3 (i,ii) dpa regenerates for PCNA (i-iv) or L-plastin (i,ii), a marker for leukocytes (mostly macrophages), and with DAPI. Scale bars: 20µm. (C) Quantification of the length of the blastema in macrophage-depleted (NTR+MTZ; n=7) and wild-type (n=6) fins at 3dpa. Macrophage-depleted fins displayed slightly decreased blastemal size compared with wild-type fins. (D) Cell proliferation (PCNA+ cells) quantified in the blastema is reduced in NTR+MTZ compared with wild-type controls. PCNA+ cell number was averaged among all sections spanning the entire fin width, and normalized to DAPI counts in the image. WT+MTZ, n=10; NTRMTZ, n=8; NTR+MTZ, n=9. *P=0.0425 (two-tailed t-test, error bars indicate s.e.m.). |