The ratio of oxidized/reduced glutathione as an index of oxidative stress in various experimental models of shock syndrome.

Red blood cells are well equipped to handle intracellular oxidative stress, their membranes are permeable to O2- and H2O2, and in this way they are important regulators of oxygen reactions occurring in their surroundings. The protective effect against reduced oxygen species - generated during the endothelial cell injury of various tissues - is attributed mainly to the glutathione metabolism of red blood cells. The blood concentration of reduced (GSH) and oxidized glutathione (GSSG) was determined by a sensitive method using glutathione reductase in experimental shock syndromes induced by paraquat toxicity, tourniquet ligature and endotoxin in rats, by bleeding and reperfusion in dogs and by transient ligature of thoracic aorta in newborn piglets. Under these conditions the concentration of GSSG was elevated and GSH was lowered, resulting in an increase in the redox ratio: [GSSG/(GSH + GSSG)] x 100 (GSSG/GSH); particularly during reperfusion. Determination of the GSSG/GSH seems to be a reliable index to assess the degree of oxidative stress "in vivo".