Precision Ligation of the Left Anterior Descending Coronary Artery Using Anatomical Landmarks in a Murine Myocardial Infarction Model

Permanent ligation of the left anterior descending (LAD) coronary artery is the most widely used approach for establishing mouse models of myocardial infarction (MI) in preclinical cardiovascular research. In conventional protocols, however, the ligation site is typically placed 1-2 mm below the left atrial appendage, a landmark that is often difficult to identify reliably during surgery. Combined with considerable inter-individual variability in murine coronary anatomy, this frequently results in imprecise LAD localization, inconsistent ligation sites, and reduced reproducibility between operators. To address these limitations, this protocol introduces the anterior interventricular sulcus (AIS) as a guiding landmark for LAD ligation. The AIS is a shallow surface groove that is directly visible under the microscope, with the LAD running immediately beneath it. Unlike conventional approaches, it provides a stable anatomical reference that supports more consistent selection of the ligation site and is easier for inexperienced operators to identify. The protocol combines standardized isoflurane inhalation anesthesia with non-invasive tracheal intubation and validates MI using electrocardiography, echocardiography, enzyme-linked immunosorbent assay (ELISA), histopathological staining, and three-dimensional coronary artery imaging. This protocol provides a reliable and reproducible experimental method for inducing MI in mice to investigate the pathophysiological and immune changes following MI.