Endotoxin and lipid peroxidation in vitro in selenium- and vitamin E-deficient and -adequate rat tissues

The effect of Salmonella typhimurium endotoxin injected intraperitoneally into rats (0.5 mg/kg of body weight) on subsequent lipid peroxidation in vitro was assessed. Peroxidation was monitored by measuring ethane production from tissue slices, as well as thiobarbituric acid-reactive substances and conjugated dienes in tissue homogenates. Weanling rats were fed a selenium- and vitamin E-deficient basal diet or one supplemented with 0.2 mg of Se/kg of diet and 200 mg of vitamin E/kg. After 9 to 16 wk, ethane production and thiobarbituric acid-reactive substances in liver and lung generally were increased by LPS treatment of Se- and vitamin E-deficient rats. Conjugated dienes were increased by LPS treatment in liver of Se- and vitamin E-deficient rats, but paradoxically, were higher in Se- and vitamin E-adequate liver tissue. Daily injections of 1 g of hydroxyurea/kg of body weight, a cell proliferation inhibitor, for 2 d prior to LPS injection significantly decreased the LPS-induced ethane production in Se- and vitamin E-deficient rat liver and lung. These results show that low doses of LPS injected into rats stimulated lipid peroxidation in vitro in Se- and vitamin E-deficient rat liver tissue. Hydroxyurea decreased LPS-induced lipid peroxidation in vitro; this suggests that neutrophils or macrophages are involved in LPS-induced lipid peroxidation.