TIME-COURSE CHANGES IN GASTRIC-MUCOSAL BLOOD PERFUSION FOLLOWING PORTAL-VEIN CONSTRICTION IN RATS

Background/Aims: Gastric mucosal blood flow is in- creased in all expe rimental models of chronic portal hypertension, when portosystemic shu nting and the hyperdynamic circulation are fully developed. However, s ome controversy exists concerning the time course of this event. This study was undertaken to investigate the chronological changes in gastr ic mucosal blood perfusion during the first 7 days after partial porta l vein constriction. Methods: Portal hypertensive and sham operated an imals were studied. Gastric mucosal blood flow was measured by hydroge n-gas clearance and gastric oxygen and hemoglobin content by reflectan ce spectrophotometry, prior to and immediately after partial portal ve in constriction, and 1, 2, 7 and 15 days after induction of portal hyp ertension. Results: Immediately after partial portal vein constriction , gastric mucosal blood flow and gastric oxygen were significantly dec reased by 27% and 32% respectively, and gastric hemoglobin significant ly increased by 19%. On day 1, gastric mucosal blood flow was increase d in both portal hypertensive and sham operated rats. However, while t his parameter returned to normal in sham operated rats, it remained hi gh on days 2, 7 and 15 in portal hypertensive rats. In portal hyperten sive rats, gastric oxygen values were not significantly different from those in sham operated animals, but hemoglobin tended to increase wit h development of portal hypertension, being significantly higher than in sham operated rats at days 2 and 7. Similar results were obtained w hen analyzing gastric mucosal blood perfusion 2 and 7 days after two-s taged total portal vein constriction. Conclusions: Increased gastric m ucosal blood perfusion is present in portal hypertensive rats from the first day after partial portal vein constriction. The lack of signifi cant differences in all parameters on day 1 between portal hypertensiv e and sham operated rats is probably related to an increased mucosal b lood perfusion related to surgery.