The early pattern of conjugated dienes in liver and lung after endotoxin exposure

If lipid peroxidation (LP) contributes to organ dysfunction in sepsis rather than simply reflecting established injury, it should occur soon after the onset of the septic insult, and it may not progress uniformly in all organs. We assessed whether LP occurs within 90 min after onset of continuous intravenous endotoxin (E. coli 055:B5) infusion in rats, using second-derivative spectroscopy to semiquantitatively assess conjugated dienes (CD) in lung, liver, and plasma phospholipids. Measurements were also made after 90-min infusions with saline or 1 mM H2O2. Both the quantity and spectrophotometric patterns of CD differed between the three groups. Compared with saline controls, lung lipid CD increased after both H2O2 and endotoxin. Venous plasma CD were elevated only after H2O2, while arterial plasma and liver lipid CD were not different between the three groups. Exhaled ethane (an indicator of peroxidation of omega-3 fatty acids) did not differ between groups. Wet-to-dry lung weights were significantly increased after endotoxin compared with that after saline controls. Our results indicate that tissue-specific LP occurs within 90 min of endotoxin or H2O2 intravenous infusion.