EFFECTS OF CHRONIC NORMOVOLEMIC ANEMIA ON GASTRIC MICROCIRCULATION AND ETHANOL-INDUCED GASTRIC DAMAGE IN RATS

The effects of chronic normovolemic anemia on gastric microcirculation and gastric mucosal susceptibility to ethanol-induced gastric damage were investigated in anesthetized rats. Blood exchange by a plasma exp ander during four consecutive days rendered the animals anemic with a 34% decrease in the baseline hematocrit but without affecting blood vo lume. Chronic anemia induced a decrease in whole blood viscosity, an i ncrease in gastric mucosal blood flow measured by hydrogen gas clearan ce, a decrease in gastric vascular resistance, and a decrease in gastr ic hemoglobin content without changes in the gastric oxygen content, t he latter two parameters being measured by reflectance spectrophotomet ry. Gastric mucosal blood flow was lowered by intragastric administrat ion of 100% ethanol in both anemic and control rats, but the final blo od flow was significantly higher in anemic than in control animals. Ma croscopic gastric damage induced by ethanol administration was signifi cantly lower in anemic than in control rats. We conclude that chronic normovolemic anemia increases gastric mucosal blood flow and leads a p rotecting mechanism against gastric mucosal damage induced by absolute ethanol.