High rate of right ventricular infarction after ligation of mid left anterior descending artery in rats

Abstract 

Background

The left anterior descending artery (LAD) supplies the left ventricle in humans. LAD ligation has been commonly used in rats to induce left ventricular (LV) infarction for research purposes. However, the myocardial supply territories of LAD are not well established in rats. We measured the infarction zone in rats after ligation of the mid-LAD.

Methods

Twenty-four male Sprague–Dawley rats weighing 300–350 g were selected for LAD ligation for the induction of ischemic cardiomyopathy. The surgery was performed under full anesthesia. Left-sided thoracotomy was performed through cuts in the fifth and sixth ribs. Ligation of the LAD was performed 1 to 2 mm distal to a line between the left border of the pulmonary conus and the right border of the left atrial appendage. LAD was ligated after the first diagonal and septal branches. After 24 h, the hearts were removed and stained with Tetrazolium Tetrachloride (TTC) for the detection of infracted areas.

Results

Ligation of LAD induces 85% infarction of the right anterior free wall and anterior right ventricular septum and induces 100% infarction of the anterior free wall of the left ventricle and anterior septum. Infarction after LAD ligation extends all the way to the distal of the ligation site down to the apex of the heart.

Conclusions

Mid-LAD ligation after the first septal and diagonal branches causes substantial right ventricular infarction in addition to LV infarct in rats. Therefore, the hemodynamic effect of right ventricle infarct should be considered in research involving LAD ligation in rats.