Oxidative injury in rat fatty liver exposed to ischemia-reperfusion is modulated by nutritional status

Abstract

Background and aims. Oxidative stress contributes to ischemia-reperfusion injury in fatty livers. This study aimed to determine whether glycogen depletion influences this oxidative injury and whether the administration of glucose can be protective. Methods. Rats with choline deficiency-induced fatty liver underwent hepatic ischemia-reperfusion. Experimental groups: (1) fed rats; (2) 18 h fasted rats; (3) 18 h fasted rats supplemented with glucose prior to surgery. The thiobarbituric acid-reactive substances, protein carbonyls and total glutathione concentrations were measured in liver tissue and isolated mitochondria as parameters of oxidative stress before and after ischemia and during reperfusion. The mitochondrial F 1-ATPase content and the serum alanine transaminase were also determined. Results. With respect to fed rats, fasted rats exhibited an increased oxidative injury in both liver tissue and isolated mitochondria throughout the experiment with the only exception of thiobarbituric acid-reactive substances, which were not affected by the nutritional status in liver tissue. Fasted rats showed a significantly lower F 1-ATPase content and higher alanine transaminase levels. Glucose supplementation significantly reduced the fasting-associated exacerbation of oxidative stress and liver injury and the F 1-ATPase exhaustion. Conclusions. These data indicate that the pre-existing hepatic glycogen content modulates the oxidative damage in rat fatty livers exposed to ischemia-reperfusion injury and that the energetic substrate supplementation may represent a clinically feasible protective strategy.