Vitamin E in relation to lipid peroxidation in experimental septic shock

Lipid peroxidation and antioxidant balance in the body is a crucial factor in the pathophysiology of various diseases. This study investigates the circulatory alpha-tocopherol levels and its relationship with 8-iso-prostaglandin F2alpha (8-iso-PGF2alpha), a non-enzymatic and, 15-keto-13,14-dihydro-PGF2alpha (15-K-DH-PGF2alpha), a cyclooxygenase catalysed oxidation product of arachidonic acid in experimental septic shock in pigs. A steady decrease in alpha-tocopherol levels in plasma was observed in both survivor and non-survivor animals. A simultaneous increase of oxidative injury indicator, plasma 8-iso-PGF2alpha was seen in both groups but with a different fashion. 8-Iso-PGF2alpha levels increased steadily in the animals that died during the experiment. An early and rapid increase of plasma 15-K-DH-PGF2alpha, an inflammatory response indicator, was also observed in all animals. There was a significant difference in the kinetics of decrement of alpha-tocopherol levels and a concomitant increase in 15-K-DH-PGF2alpha levels among the non-survivors. Thus, a successive disappearance of circulatory vitamin E in conjunction with the surge of plasma isoprostanes and prostaglandins impairs the oxidant-antioxidant balance in favour of the former and may possibly have an effect on the survivality during experimental porcine septicaemia.