Figure 4.

GFP and vimentin double‐positive cardiac fibroblasts persisted for at least 8 weeks. Immunostaining against GFP (green) and vimentin (red) in Axin2‐CreERT2;mTmG neonates that received tamoxifen injection either (A) before injury on P0 or (B) 9 days after injury on P10 and were traced for 8 weeks. Arrowheads indicate double‐positive cells. Scale bar=20 μm. C, Trichrome staining of injured hearts at 7 days, 21 days, and 3 months after injury revealed extensive scarring that persisted to up to 3 months. Scale bar=0.5 mm.