Figure 3

Heart regeneration in mvp KO fish. (A) Visualization of epicardial cells in control and mvp^−/− fish. Epicardial cells proliferate by 7 dpi and are incorporated into the regenerating myocardial wall. Inset shows enlarged view of boxed area. Bar graph showing the density of epicardial cell at surface of hearts from control and mvp^−/− fish. Data are mean ± SEM. For each group, eight samples were assessed. n.s, not significant. (B) Cardiomyocyte proliferation at 7 days post-amputation (dpa) in ventricular sections from control and mvp^−/− animals, assessed by Mef2 and PCNA staining. Arrowheads, the PCNA positive. Scale bar = 100 μm. Bar graph showing cardiomyocyte proliferation indices on 7 dpa in control (n = 8) and mvp^−/− (n = 8) fish. Proliferation data were collected for 4–6 sections per heart and averaged to generate each data point. Data are mean ± SEM. n.s, not significant. (C) Section images of ventricles at designated time points, assessed for myocardium (MHC) recovery and scar tissue (fibrin, collagen) removal. In A, B and C, dashed line indicates approximate resection plane.