Apical Resection Neonatal Mouse Model: A Surgical Procedure to Amputate the Ventricular Apex to Study Regenerative Potential in a Neonate Mouse Heart

Apical resection of a neonatal mouse is a procedure to remove the left ventricular apex of the heart. The resulting injury activates neonatal cardiac macrophages that promote cellular processes for cardiac repair.  However, this regenerative ability becomes limited in adulthood, leading to heart failure.  Transplanting neonatal cardiac macrophages into the adult heart can restore cardiac function.

To begin, place a neonatal mouse on ice to induce hypothermia that numbs the mouse. Transfer and prep the unconscious mouse on a surgical platform. Now, under a stereoscope, horizontally incise the left side of the chest and separate the underlying muscles to visualize the heart.

Apply pressure on the chest and abdomen to exteriorize the heart. Carefully cut off the ventricular apex tissue till bleeding exposes the left ventricular chamber. Using a cotton swab, press the heart back into the chest cavity. Suture the incised chest wall.  Apply tissue glue to join the skin. Subsequently, transfer the mouse to a heating blanket to stop hypothermia. Then, shift the operated neonatal mouse to its mother's cage for a speedy recovery.

Following apical resection, the resident cardiac macrophages accumulate in the injured site. Subsequently, these macrophages can be isolated for transplantation into the adult heart.