Lipid peroxide formation and membrane damage in endotoxin-poisoned mice

Lipid peroxide formation and plasma membrane damage in mouse liver following the administration of Salmonella endotoxin were examined. The liver lipoperoxide level was markedly elevated in animals given endotoxin compared with that in the controls, and returned to its normal range after 2 days. On the other hand, superoxide dismutase activity was decreased by 18--48 hr after endotoxin injection, thereafter tending to increase. Glutathione reductase and glutathione peroxidase activities declined in the liver 18 hr after the injection. The endotoxin resulted in much lower lipoperoxide formation in the livers of tolerant mice than in those of the poisoned mice. The lipoperoxide level in endotoxin-poisoned mice after the administration of alpha-tocopherol was lower than that in the controls, and alpha-tocopherol administration prevented completely the membrane protein damage that arose from endotoxin challenge. After glutathione administration the membranes of the poisoned mice also returned to almost the normal disk electrophoretic profile. These results suggest that lipid peroxide formation in the liver plasma membrane caused by free radicals might occur in a tissue ischemic state in endotoxicosis.