Heart Dissection: A Method to Observe Zebrafish Cardiac Development

- A zebrafish heart comprises four chambers, sinus venosus, atrium, ventricle, and bulbous arteriosis. It is located anteriorly on the ventral side between the operculum and the pectoral girdle, a part of the skeletal system that supports the pectoral fin. To dissect the heart, place a euthanized fixed fish into a Petri dish containing phosphate-buffered saline to maintain a constant pH of the fish tissues and orient it ventral side up.

Hold the fish head with forceps between the eyes and gills. Using a microscissor, cut across the gills, across the anterior belly, and then vertically, connecting the first two incisions. With a sharp tweezer, remove the pectoral fin and the underlying pectoral girdle to reveal the silver pericardium, the membrane that covers the heart. Remove the pericardium with forceps to make the heart visible. Now cut the artery connected to the bulbous arteriosis.

Next, place forceps under the atrium and scoop the heart out of the body cavity. Hold the heart with the forceps, and use another forceps to remove unwanted tissue present outside the heart. In the following protocol, we will dissect the heart from different sized fish to image its development over t