Fig. 3.

Rapid regeneration of ventricular cardiomyocytes after ablation-induced injuries. (A) Myosin heavy chain (MHC) staining of ventricular sections from Z-CAT fish injected with vehicle or 4-HT, at 7, 14 and 30 days post-injection (dpi). For each group, 5-7 animals were assessed. (B) Quantification of MHC⁺ myofiber area from experiments in A. (C) Quantification of Mef2⁺ cardiomyocyte nuclei from experiments in A. (D) Ventricular cardiomyocyte proliferation at 14 dpi assessed by Mef2 and PCNA staining. 4-HT-injected animals display widespread PCNA⁺ cardiomyocytes. (E) Quantification of ventricular cardiomyocyte proliferation in Z-CAT animals injected with vehicle or 4-HT, at 7, 14 and 30 dpi. For each group, seven to nine animals were assessed. ^*P<0.05, ^**P<0.005, Student's t-test. Mean±s.e.m. Scale bars: 50 μm.