This article details the procedure of aortic banding and subsequent debanding in mice to study cardiac hypertrophy and fibrosis. The methodology includes surgical techniques and postoperative monitoring to assess heart recovery.
Aortic banding is performed by ligating the transverse arch of the aorta, between the innominate artery and the left common carotid artery. This constriction leads to increased ventricular pressure, causing hypertrophy of cardiomyocytes where muscle cells of the heart become enlarged.
Simultaneously, there is an accumulation of extracellular matrix proteins in the interstitial space, culminating in ventricular fibrosis. To reverse these fibrotic and hypertrophic effects on the heart, take an anesthetized mouse a few weeks after undergoing aortic banding. Place the mouse in the supine position and prep it by removing the fur from the chest.
Make a small incision on the left side of the chest to locate the heart and its connecting vessels. Visualize the aorta and the suture tied to it. Perform aortic debanding by cutting this suture to remove the constriction in the aorta. Finally, close the muscle and skin layers.
Transfer the mouse to a cage and monitor for postoperative recovery of the heart. After successful debanding, there is reduction in extracellular matrix proteins resulting in diminished fibrosis. The mouse also exhibits a gradual reduction in the size of cardiomyocytes and mass of ventricles, indicating a regression in hypertrophy and improving overall cardiac output.
Seven weeks after the banding surgery, gently dissect the tissues, adhesions, and fibrosis around the aorta in half of the banded animals until the constriction becomes visible. Carefully dissect the aorta and separate the suture from the vessel. Then, use scissors to cut the suture.
Note that a prolonged occlusion of the ascending aorta during banding or debanding may lead to lung edema and excessive activation of inflammatory pathways.
Close to the chest wall with a simple interrupted or continuous 6-0 polypropylene sutures using the minimum number of stitches possible and close the skin with a 6-0 silk polypropylene suture in a continuous suture pattern. Then, perform the post-operative care as demonstrated.
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