Fig. 3

Ptprz1b^−/− zebrafish larvae have defective heart rate (HR), enlarged ventricles, and defective contractility. A: Ptprz1b^+/+ and ptprz1b ^−/− embryos at 80 hpf exhibit similar morphology (images are lateral views, anterior to the left, dorsal to the top). Ptprz1b ^−/− embryos exhibit lower blood flow (black arrows, embryo tails). Scale bars correspond to 100 μm. B: HR expressed as means ± SD (ptprz1b^+/+: n = 30 and ptprz1b^−/−: n = 20); statistical analysis was performed by Student’s unpaired t test. C: microscope images illustrating the morphology of 5 dpf ptprz1b^+/+ and ptprz1b^−/− mutants as seen from a left lateral. The heart area is marked with a white dashed box. Scale bars correspond to 500 μm. D: representative images of 5 dpf embryos’ hearts (vertical view) at fully diastole phase. Images are individual frames from high-speed microscope imaging, recording embryonic cardiac beating. The ventricular area of the heart is highlighted, with the length (long axis) and width (short axis) of the ventricle indicated by dashed lines. Scale bars correspond to 50 μm. E: quantification of cardiac function at 5 dpf. Results are expressed as means ± SD (ptprz1b^+/+: n = 30, ptprz1b^−/−: n = 20) and statistical analysis was performed by Student’s unpaired t test and Mann–Whitney test. A, atrium; BA, bulbous arteriosus; CO, cardiac output; dpf, days postfertilization; EDV, end-diastole volume; ESV, end-systolic volume; %EF, percent ejection fraction; %FS, percent fractional shortening; SV, stroke volume; V, ventricle.