RESUMEN
Coronary ligated rats were administered intraperitoneal injections of 6.24, 12.52, and 25.00 mg . kg-1 ibuprofen and 5.00 and 10.00 mg . kg-1 verapamil 1 h before ligation, 1 h after ligation, and then every 8 h for 48 h. Ibuprofen at 50.00 mg . kg-1 was administered 1 h before ligation, 1 h after ligation and 5 h after ligation. Infarct size was determined either by weighing the stained excised infarcted area or by measuring the creatine kinase activity from the excised left ventricle. Ibuprofen and verapamil treatment resulted in less myocardial damage after 48 h than placebo treatment but the differences were generally not statistically significant. The reduction in infarct size was greater in the ibuprofen treated animals compared with verapamil treated rats. In addition, there was a lower mortality with ibuprofen treatment than for either verapamil or placebo. This rat model was useful as a screening tool for the initial evolution of therapeutic interventions to reduce myocardial infarct size. It required substantially less time than large animal models and can be used to examine a variety of treatment doses. These experiments also demonstrated the importance of randomisation to treatment and control groups because of the possibility of disproportionate mortality affecting infarct size.