Acute lesion of rat myocardium by a single injection of cobalt dichloride.

The formation of infarctoid areas in rat myocardium following intraperitoneal injection of cobalt dichloride (30 mg/kg) is connected with metabolic (toxic) and ischaemic lesions of myocardial cells. The ischaemic lesions are sequelae of thrombosis taking place after 3-8 hours in consequence of thrombocytic aggregation in the capillary lumen. With the aid of polarization and electron microscopy, the myocardial-cell changes in the affected zones were classed into four morphological types, as follows: contracture type, intracellular myocytolysis, primary clumpy disintegration of myofibrils, and intravital autolysis of ischaemized cells.