Fig. 4

Cardiac regeneration is delayed in nrp1a^sa1485 mutants following cryoinjury. (A) Heart sections from wild-type (top) and nrp1a^sa1485 mutant (bottom) fish obtained at 1, 3, 7, 14, 30 and 60 dpci and stained with AFOG to identify the injured region. Dashed lines indicate the interface between cryoinjured and healthy tissue. (B) Cryoinjured areas were measured and represented as mean percentage of total ventricle area±s.e.m. P<0.05 (two-way ANOVA with Sidak's post hoc test for multiple comparisons of n=4-8). (C) A closed wound is one in which compact myocardium recovers following cryoinjury and encases the scar tissue; by contrast, a scar exposed to the surface is defined as an open wound. Wound closure was examined in wild-type (WT) and nrp1a^sa1485 mutant hearts at 30 and 60 dpci and open versus closed wounds were expressed as a percentage of the total number of hearts (n=4-8). (D,E) AFOG staining of wild-type and nrp1a^sa1485 mutant hearts at 3 dpci (D) used to evaluate epicardial thickness and injury boundaries to calculate the epicardial area normalized to the length of the injury boundary (continuous line), quantified in E. Dashed line represents outer boundary of epicardial area. *P<0.05 (two-tailed t-test of n=7 for wild-type and n=10 for nrp1a^sa1485 hearts). A, atrium; ba, bulbus arteriosus; V, ventricle.