Infarct size in rabbits: a modified method illustrated by the effects of propranolol and trimetazidine

Following a 45-min period of coronary occlusion the myocardial infarct that developed after 24 h of blood reperfusion in the rabbit heart was studied in three groups of animals: controls (n = 7), and those pretreated with 3 mg.kg-1 of the piperazine derivative, trimetazidine (n = 7) or propranolol at 0.3 mg.kg-1 (n = 6). Twenty-four hours after coronary artery ligation for 45 min infarct size was measured in myocardial slices using trinitrophenyl-tetrazolium staining, and the "area at risk" was determined by injection of zinc/cadmium particles and delineated by imaging under fluorescent light the areas of tissue that did not fluoresce. The range of "area at risk" was similar in all of the groups. There was a significant reduction in the size of infarct that developed in the trimetazidine treated group when compared with the controls. In the propranolol treated group there was a slight reduction in infarct size when compared to control, but this was less than in the trimetazidine treated group and did not reach statistical significance. It is concluded that pretreatment with trimetazidine in the blood perfused rabbit heart is effective in reducing myocardial infarct size.