Background: Left anterior descending artery (LAD) ligation has been commonly used in rats to induce left ventricular infarction for research purposes. However, LAD ligation is a very difficult procedure with high mortality rate in rats. We have developed a safe method of LAD ligation in rats with low mortality.
Methods: Thirty-six Sprague-Dawley male rats weighing 300-350 g were selected for LAD ligation for the induction of ischemic cardiomyopathy. The surgery was performed under general anesthesia. Left-sided thoracotomy was performed by cutting the fifth and sixth ribs. The pericardium was opened, and the heart exteriorized with a cardiac holder consisting of a plastic loop (1.5x2 cm). The LAD was localized 1-2 mm below the junction of pulmonary conus and the left atrial appendage. A 5.0 silk suture was used to ligate the LAD from the left border of the pulmonary conus to the right border of the left atrial appendage. The heart was returned back to the chest and the chest wall closed with presutured lopes of 4.0 silk.
Results: Mid-LAD ligation was successful in all rats, with less than 5% mortality. The entire surgery was performed in less than 15 min. This method is simple and can be learned in a short period of time. Rats survived the procedure with induction of congestive heart failure for up to 3 weeks of follow-up.
Conclusions: Using our method, LAD ligation can safely be performed in rats 1-2 mm below the junction of the pulmonary conus and the left atrial appendage, with a very low mortality rate.