TALEN‐targeted animals show increased macrophage and monocyte infiltration in regenerating limbs and decreased stump collagen deposition. NSE staining was performed to detect monocytes and macrophages in regenerating juvenile limbs at 6 days post‐amputation. (A) Wild‐type sibling control. (B) TALEN‐targeted tsp‐1 deletion animal. (C) The quantification of NSE positive cells (A, B, black) within the blastema mesenchyme were quantified (N = 14, 6, 16 limbs for wt, TAL1 and TAL2 respectively). (D), (E) Subepidermal collagen thickness was measured (yellow double arrow) in control and TALEN‐targeted stumps, and quantified in (F) (N = 14 controls; 6 TAL1; 16 TAL2). Scale bars in all images are 50 μm; *P < 0.05, **P < 0.01; error bars indicate SEM.