Inhibiting effect of dexamethasone on evolving myocardial necrosis in coronary-ligated rats, with and without reperfusion.

Previous findings suggested that glucocorticosteroids may be able to preserve ischemic myocardial tissue from cellular necrosis. In the present investigation, the left coronary artery in rats was ligated either permanently, or reperfusion was allowed after an occlusion time of 40 min. After 5 h of permanent coronary ligation, or after 60 min of reperfusion, respectively, the hearts were investigated as to the extent of their ischemic and necrotic areas. The ischemic areas were determined by 'negative staining' with Evans blue, and the necrotic areas by 'negative staining' with triphenyltetrazolium chloride. Dexamethasone orthophosphate in both kinds of experiments significantly decreased the percentage of the ischemic area which had undergone necrosis.