Effect of hemorrhagic shock on oxidative phosphorylation and blood flow in rabbit gastrointestinal mucosa

The pathophysiologic mechanism responsible for ulceration of gastric fundus and corpus mucosa following hemorrhagic shock is not well defined. We examined the effect of hemorrhagic shock (25 ml blood/kg) and resuscitation (reinfusion of shed blood) on oxidative phosphorylation in different tissues of the rabbit to determine if differences in mitochondrial response to hemorrhagic shock and resuscitation contribute to the propensity of gastric fundus and corpus to necrose before other tissues. Blood flow was measured by using radioisotope-labeled microspheres to determine if changes in regional blood flow could be correlated with this propensity to ulcerate. The respiratory control index (RCI), an index of the integrity of mitochondrial function, was significantly increased in gastric antrum, liver, and kidney from the animals subjected to hemorrhagic shock and successful resuscitation when compared to control animals. In liver and kidney, these differences were largely due to increases in state 3 respirations. Duodenal and gastric corpus and fundus mitochondria showed no differences in RCI between bled and control groups. Blood flow data did not implicate ischemia as the mechanism responsible for the differential rate of ulceration after hemorrhage. The inability of fundus, corpus, and small-bowel mucosal mitochondria to respond to the stress of hemorrhagic shock and resuscitation in a manner similar to liver, kidney, and gastric antral mitochondria may place these tissues at greater risk to ulcerate. Further work is necessary to define whether this difference in mitochondrial response patterns represents a real increase in the maximal respiratory capacity of liver, kidney, and antrum after shock and resuscitation.