A characterization of myocardial infarction induced by thrombotic occlusion and a comparison with mechanical ligation of the rat coronary artery

In the present study we examined two different methods for inducing myocardial infarction in rats. We previously developed an animal model of coronary artery thrombotic occlusion induced by a photochemical reaction, which occurs when rose bengal (a photosensitizer dye) is injected into the animal and is irritated with green light. Arterial occlusion is thereby achieved nonmechanically. Using this method, we investigated the effect of thrombolytic intervention on myocardial infarct size. Infarct size was determined 24 h after the induction of myocardial infarction. When tisokinase (3mg/kg), a native tissue-type plasminogen activator, was administered 3 min after the ST-segment elevation on a lead II electrocardiogram, the infarct size was 20.6 +/- 5.1%, which was significantly smaller than that of control rats (37.3 +/- 4.6%). When tisokinase was administered 10 min after ST-segment elevation, the infarct size was 27.1 +/- 2.1%, which was significantly smaller than that of controls. The rat coronary artery thrombosis model incorporates many aspects of coronary thrombosis. it differs from the coronary ligation model in that it lends itself to the study of thrombolytic agents on animal models of myocardial infarction. (C) 2001 Prous Science. All rights reserved.