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Effect of 6-methyluracyl (MU) on oxidative processes was studied on model systems of different degrees of complexity (methyloleate model, mitochondria isolated from rat liver, surviving slices of mammalian muscle tissues). On two former models it was shown that MU exerted antioxidant (AO) properties inferior to those of such antioxidants as ionol and K(+)-phenosan. The AO efficiency depended on the intensity of peroxide processes. The AO activity of MU was most fully realized on the model of isolated surviving slices of muscle tissue. The totality of data obtained suggests that participation of the substance in regulation of lipid peroxidation in the organism underlies its therapeutic activity in pathological states.

The anti-ischemic and toxic effects of different doses of the antioxidant ionol (butyl hydroxytoluene, BHT) introduced into the Krebs-Henseleit medium composed of monolayer liposomes of egg phospholipids before or 30 minutes after total ischemia of the heart were studied on a model of perfusion of isolated Wistar rat heart by the method of Langendorff-Fallen. It has been demonstrated that ionol, after its addition to the perfusate in the preischemic period, exerts an anti-ischemic effect in concentrations of 10(-6), 3 x 10(-6) and 10(-5) M; in the postischemic period, in concentrations of 3 x 10(-6) and 10(-5); the protective effect of ionol in the postischemic period is less pronounced. In higher doses (3 x 10(-5) and 10(-4) M) ionol produces a toxic action which is more remarkable and is less reversible in respect to the ischemized than to the nonischemized heart, and is realized rather through the dysfunction of heart muscle relaxation. The conclusion is drawn that there is a possibility of using ionol in doses of 10(-6) to 10(-5) M as a constituent of liposomes for addition to perfusion, conservant and cardioplegic solutions as an anti-ischemic remedy.

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.