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

Modest acute hypovolaemia in rats markedly decreases the duodenal mucosal a lkaline secretion via neurohumoral links. The present study was undertaken to investigate ii such a procedure influences the morphological changes obs erved 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. Mu cosal damage was evaluated by light microscopic morphometry on transverse s ections and by scanning electron microscopy of the luminal surface. Perfusi on 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 1 0% by 100 mM HCl as compared with NaCl lime controls. Hypovolaemia did not influence the morphometrical changes induced by 10 mM, HCl but reduced sign ificantly both villus length (-28%) and villus area (-10%) as compared with the unbled 100 mM HCl group. Scanning electrone microscopy (SEM)-based vis ual damage score was not influenced by the hypovolaemia procedure in any of the acidities. Morphological changes of the duodenal mucosa, induced by mo derate 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.