A simple technique for occlusion and reperfusion of coronary artery in conscious rats

A simple technique to occlude and reperfuse the coronary artery of conscious rats, which can freely move about, has been developed. After rats had been anesthetized and thoracotomized, the left coronary artery (LCA) was tied loosely (an occluder), and two other sutures (releasers) were tied to the knot so that it could be loosened to allow for reperfusion. Acute LCA occlusion (0.5 h) with reperfusion (3.5 h) or permanent LCA occlusion (4 h) was done to different groups of rats. Almost the same infarct size had formed in rats of either group (approximately 60% of the left ventricular weight); however, when arterial blood flow was restored (occlusion with reperfusion group), scattered bleeding and cell damage occurred. Plasma concentration of creatine phosphokinase (CPK) (4-h permanent occlusion group) increased by approximately 400%, which depended on infarct size (r = 0.89, P less than 0.001); whereas CPK concentrations in the occlusion with reperfusion group were significantly low. After permanent LCA occlusion or reperfusion occlusion, approximately 40% of the rats died of ventricular fibrillation within 4 h, and most of them died within the first 30 min. In the occlusion with reperfusion group, an additional number died as a result of reperfusion. Electromyocardiograms clearly reflected the regional ischemia as evidenced by an increase of 2-2.5 mV in the S-T segment; the phenomenon disappeared after reperfusion. In conclusion, our simple technique could be used to study the biochemistry, electrophysiology, and morphology of a conscious animal that has undergone occlusion with reperfusion of the LCA.