Transverse Aortic Arch Banding in Mouse Model: A Minimally Invasive Technique in Mice for Induction of High Pressure in the Left Ventricle

Minimally invasive transverse aortic constriction or aortic arch banding is a simplified procedure to generate a mouse model of cardiovascular disease. Begin with an anesthetized mouse in the supine position. Shave the neck and the chest region. Perform a midline incision to expose the underlying muscle layer.

Slit through the muscle layer to access the thyroid gland and sternum. Next, separate the tracheal muscles and cut the sternum to reveal the underlying thymus gland. Separate the thymus lobes from one another to reveal the transverse aortic arch and carotid arteries. Place a curved needle under the aortic arch and push it out between the vessel wall.

Pass a ligature through this perforation and place a spacer in the loop to adjust the loop diameter. Now, tighten the suture around the aorta to occlude the vessel. This increases the blood-flow velocity in the right carotid artery, causing increased blood pressure in the ascending aorta and the left ventricle.

Thereafter, remove the spacer and cut the thread. Then, reposition the organs and suture the skin. Transfer the mouse to the recovery cage and monitor its cardiac function. Aortic banding induces left ventricular overload, leading to thickening of chamber walls and diminished cardiac output.

Before beginning the procedure, use a needle holder to curve the tips of two to four 30-gauge needles and mount the needles onto individual cotton applicators. Next, blunt a 27-gauge needle and use the needle holder to bend the tip 90 degrees. Then, smooth the tip on a hard surface to make a 0.4-millimeter spacer. After confirming the appropriate level of sedation by a lack of response to toe pinch, apply ointment to the animal's eyes and place the mouse on a 37 degrees Celsius warmed heating pad in the supine position.

Secure the limbs to the heating pad with surgical tape. Then, disinfect the skin with three consecutive alcohol and povidone-iodine solution wipes and place a sterile drape with an exposed operation field over the animal. To begin the ligation procedure, use a sterile scalpel to open the skin at the midline position of the neck and chest. Next, under a dissecting microscope, use blunt scissors to gently separate the connective tissues and pull the thyroid gland towards the head.

Using the curved needles, separate the muscle layer on the trachea at the midline towards both sides of the animal and use the blunt scissors to cut the sternum approximately 5 millimeters to the second rib. Open the incision with curved forceps and use a curved needle to separate the thymus lobes and the lower chest wall. The transverse aortic arch and two carotid arteries will be clearly visible at this point.

Place the curved needle under the arch and use the tip to make a perforation between the vessel wall and the connective tissue on the other side. Use the needle to place a 6-0 monofilament suture under the aortic arch and place the previously prepared spacer into the loop. Fix the suture in place with a double knot and gently remove the spacer.

After confirming a successful knot constriction, cut the ends of the suture and use a 6-0 silk suture to close the chest wall with a simple interrupted suture pattern, followed by closure of the skin with a 6-0 monofilament suture in a continuous suture pattern. Then, apply povidone-iodine solution to the suture site and place the animal in a pre-warmed cage for recovery and post-operative monitoring.