Effects of hypovolaemia on acid-induced duodenal mucosal damage in the rat.

Abstract

Modest acute hypovolaemia in rats markedly decreases the duodenal mucosal alkaline secretion via neurohumoral links. The present study was undertaken to investigate if such a procedure influences the morphological changes observed following an acid challenge of the duodenal mucosa. Experiments were performed on anaesthetized male Sprague-Dawley rats. HCl (10 or 100 mM) was infused during 15 min into the duodenum via a luminally situated catheter. Time controls were compared with animals bled 10% of total blood volume. Mucosal damage was evaluated by light microscopic morphometry on transverse sections and by scanning electron microscopy of the luminal surface. Perfusion with either 10 mM or 100 mM HCl reduced villus length by about 30%. The villus area was unaffected by 10 mM HCl, but was reduced significantly by 10% by 100 mM HCl as compared with NaCl time controls. Hypovolaemia did not influence the morphometrical changes induced by 10 mM HCl but reduced significantly both villus length (-28%) and villus area (-10%) as compared with the unbled 100 mM HCl group. Scanning electrone microscopy (SEM)-based visual damage score was not influenced by the hypovolaemia procedure in any of the acidities. Morphological changes of the duodenal mucosa, induced by moderate intra-luminal acidity (10 mM HCl), is not influenced by hypovolaemia. However, at higher acidities (100 mM HCl) the hypovolaemia contributes to more severe mucosal damage.