Depression of the reticuloendothelial system following graded isoproterenol-induced myocardial injury.

The effect of experimental myocardial injury on reticuloendothelial system (RES) phagocytic function was investigated. Graded myocardial injury was produced in rats by the subcutaneous injection of isoproterenol in doses of 5, 50 or 500 mg/kg. Phagocytic index, determined from the clearance rate of gelatinized lipid emulsion at six hours after isoproterenol injection, showed a progressive depression with increasing severity of myocardial injury. The depression in phagocytic index was due primarily to a depression of hepatic phagocytosis. RES blockade induced with colloidal carbon prior to isoproterenol injection (650 mg/kg) increased the mortality rate from 20% to 87%. It was concluded that the depression of RES function during this form of myocardial injury may hasten the deterioration of the organism and that it may be important to consider the role of RES function during clinical cardiogenic shock.