Image analysis of effects of 4 drugs on coronary occlusion and myocardial reperfusion injury

Myocardial infarction induced by coronary occlusion (O model) and reperfusion (R model) and the effects of nitroglycerin (Nit), propranolol (Pro), lidocaine (Lid), nifedipine (Nif), and saline were studied in rats by image analysis and weighing methods. The results showed that the myocardial infarct size (MIS) in R and O models were 27 +/- 8% and 39 +/- 6%, respectively (P < 0.01). The roundness and the distances from the border of the infarct zone (IZ) to endocardium or epicardium in R model were greater than those in O model, while the gray level difference between normal and infarct myocardium (delta G) in the R model was less than that in O model. MIS of Nit group in O and R models were 23 +/- 12% and 16 +/- 7%, respectively, which were significantly less than those in Lid, Nif groups, and saline. The reduction of MIS was also found in Pro group in both models. The results suggested that early restoration of blood flow resulted in the salvage of injured myocardium and Nit and Pro were found to have beneficial effects in both models.