AJP - Gastrointestinal and Liver Physiology, Vol 253, Issue 2 129-G133, Copyright © 1987 by American Physiological Society
Gastric injury induced by hemorrhage, local ischemia, and oxygen radical generation
S. S. Wadhwa and M. A. Perry
Gastric mucosal injury caused by local intra-arterial generation of
oxygen-derived free radicals was compared with gastric injury caused by 30
min of hemorrhage-induced ischemia (systemic pressure of 30 mmHg) or local
ischemia (celiac artery pressure of 30 mmHg). The index of injury was the
loss of 51Cr-labeled red cells across the gastric mucosa. Generation of
oxygen radicals in the celiac artery caused a rapid increase in mucosal
blood loss during the period of radical generation (0.029 +/- 0.013 ml X
min-1 X 100 g-1, mean +/- SE), and this loss was maintained after radical
production ceased (0.041 +/- 0.018 ml X min-1 X 100 g-1). Local ischemia
produced similar mucosal injury; however, this occurred after reperfusion
of the stomach (0.038 +/- 0.006 ml X min-1 X 100 g-1) and not during the
ischemic episode (0.001 +/- 0.0003 ml X min-1 X 100 g-1).
Hemorrhage-induced ischemia produced a threefold greater mucosal blood loss
(0.133 +/- 0.048 ml X min-1 X 100 g-1) than local ischemia. The results of
this study indicate that oxygen radicals generated enzymatically in the
blood supply to the stomach cause mucosal bleeding of similar magnitude to
that observed after local ischemia and that gastric ischemia induced by
systemic hypotension produces more severe gastric injury than the same
level of local hypotension.
