Fasting augments lipid peroxidation during reperfusion after ischemia in the perfused rat liver

Abstract

Objective: To test the hypothesis that fasting would aggravate postischemic lipid peroxidation in a perfused rat liver model.

Design: Prospective, randomized study in a rat perfused liver model.

Subjects: Male Sprague-Dawley rats.

Interventions: Livers isolated from fed and fasted male Sprague-Dawley rats (n = 16) were exposed to 2.5 hrs of normothermic (38 degrees C) ischemia followed by 2 hrs of reperfusion.

Measurements and main results: Lipid peroxidation was measured by chemiluminescence and thiobarbituric acid reactive substances (TBARS). Injury parameters, potassium, lactate dehydrogenase efflux, and oxygen extraction were measured every 30 mins. Chemiluminescence and TBARS were greater in the fasted ischemic group during reperfusion. (fasted vs. fed: chemiluminescence, 946.8+/-205.5 [SEM] vs. 98.1+/-8.2 counts per second, p = .0004; thiobarbituric acid reactive substances, 1.11+/-0.25 vs. 0.21+/-0.032 nM/g of liver wt/min, p = .0019). Potassium efflux in the fasted group was greater than in the fed group. (1.568+/-0.082 vs. 1.28+/-0.079 microEq/g liver weight/min, p = .0184). Fasted livers extracted less oxygen after ischemia (1.94+/-0.22 vs. 1.14+/-0.46 microM/g liver wt/min, p = .0048). Lactate dehydrogenase levels showed no significant differences.

Conclusion: Fasting augmented lipid peroxidation markedly. Nutrition may be an important mechanism that protects organs from oxidative injury.