Pathophysiologic changes of local ischemic coronary artery and cardiac muscle after ligating canine LAD

AIM: To evaluate the reliability of making a research model of coronary artery stenosis and local myocardial infarction reproduced in dog by ligating canine LAD. METHODS: We disparted 30 aged healthy cross-breed dogs ［(18.5±6.7) kg］ into three groups. The near part of the LAD through left minimal thoracic incision was ligated to interdict 25% (group A), 50% (group B), 75% (group C) of the flux, respectively. The changes of plasma endothelium-derived factors NO, ET-1, sP-selectin and CTnT were measured before ligation and at different time points after ligation. The expression of P-selectin gene in cardiac muscle was detected by Western blotting. The segments of distal parts of the ligated LAD were cut and pathological changes of the patches of topical cardiac muscle were observed by electronic microscope. RESULTS: After ligation, NO/ET-1, P-selectin and CTnT had significant changes in group B (P<0.05) and group C (P<0.01). The expression of P-selectin of cardiac muscle was highly up-regulated after ligating in B (50%) and C (75%) group, In C group animals, a typical far more intense expression pattern was found. Under electronic microscope, the endothelium and other structures of the LAD wall and ultrastructure of myocardial cells had obvious changes in later two groups, especially in group C. There were a typical stenosis of LAD and myocardial infarction. CONCLUSIONS: Ligating the LAD 75% severely damages the endothelial cell and cardiac muscle cells of local ischemic vessel and cardiac muscle, thus forms the typical local stenosis of coronary artery and myocardial infarction, such method is a safe and reasonable way for making a disease model for studying CABG in surgery.