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In experiments on perfused isolated Wistar rat hearts and frog myocardial strips it has been shown that the injection of egg phospholipid liposomes in the perfusion solution leads to a decrease in the volume velocity of the coronary perfusion and to worsening of the contractile myocardial function. Negative inotropic effect of phospholipids on the perfused heart may be linked not only with the decrease in the coronary perfusion but also with their direct inhibitory action on the contractile ability of myocardiocytes.

Experiments were made on Wistar rats with 6h tourniqueting of the hind limbs to study animal survival rate, myocardial contractile function and protective action of antioxidants and egg phospholipid liposomes during ischemic shock. It has been shown that reperfusion of the limbs leads to a high animal lethality, make lower myocardial contractile function and coronary flow of the hearts isolated from rats following a 6h reperfusion of the limbs. Well-known antioxidant butylated hydroxytoluene and a new antioxidant tetramethylpiperidine derivative bring animal lethality down and improve coronary flow and contractile function of the isolated heart. Phospholipid liposomes increase survival rate moderately but have no any effect on the heart contractile function. It has been deduced that lipid peroxidation takes part in the disturbance of heart contractile function and genesis of the death within ischemic shock.

Effects of oxidized yolk phospholipids (PL) on the coronary perfusion rate (CPR) and myocardial contractility were studied in the experiments with the isolated or isolated and 30-minute ischemia-induced heart of the rat or isolated myocardial strip of the frog. The oxidized PL were demonstrated to possess a more pronounced and steady negative inotropic effect than unoxidized PL, which was due to their direct dose-dependent damaging action on myocardial contractility. The oxidized PL also made the unrestored CPR worse in the early postischemic period, the concomitant administration of aspirin producing no effects and that of the antioxidant ionol making ischemic myocardial contractility better. The findings suggest that the circulating oxidized PL may contribute to the impairment of coronary tone and contractility of the intact or ischemic myocardium and the induction of endogenous processes of lipid peroxidation plays a role in showing these effects.