Figure 2

Surgical procedure for sham operation and apex resection (AR). (A) Instruments and utensils required for AR and sham surgery in zebrafish, details are specified in materials and methods. (B–J) Pictures demonstrating each major step in AR surgery (See Supplementary Video S2 for AR and Supplementary Video S3 for sham surgery). (B) Locating the beating heart. (C) Use the forceps to gently lift up the skin. (D) With the micro scissors make a small incision just above the heart. (E) Widen the incision with the forceps. (F) Gently applied pressure on the sides of the incision will make the heart “pop out”. (G) 10–20% of the apex is resected, white arrow marks the resected piece. (H) Remove the instruments and let the heart get back in place before wiping away the blood. (I) The wound after the procedure. (J) The recovering zebrafish (See Supplementary Video S4 for details regarding recovery). (K) Haematoxylin and eosin (HE) stained section from sham and AR hearts 2 h post injury (hpi) showing the heart and where the bulbus should be located as well as the fibrin/blood clot at the resection site. Scalebar: K = 300 µm.