Changes in gastrointestinal morphology associated with obstructive jaundice

Bacterial translocation has been consistently demonstrated in experimental models of obstructive jaundice. An important factor which promotes this phe nomenon is physical injury of the intestinal mucosa. Some previous studies have presented suggestive evidence of this, following bile duct ligation, T he aims of this study were to analyse objectively intestinal mucosal morpho metric characteristics, to examine for evidence of bacterial translocation, and to assess enterocytes for ultrastructural abnormalities. Adult female Wistar rats were assigned to one of three groups: control (n=8), bile duct ligation (BDL; n=11), or sham operation (n=10). One week later, portal bloo d, mesenteric lymph nodes, liver, and spleen were harvested and cultured ae robically and anaerobically for evidence of bacterial translocation. Segmen ts of jejunum, ileum, caecum, and large bowel were examined histologically, using light microscopy and morphometrically, using an image analysis syste m. Electron microscopy was performed on regions of the gastrointestinal tra ct where significant morphometric alterations had been identified. Signific ant bacterial translocation was identified following BDL (63.6% BDL vs. 0% sham vs. 0% control, p<0.01, Fisher's exact test). There was a significant reduction in total mucosal thickness (standard error) [650 <mu>m (23) BDL v s. 731 mum (27) sham vs. 744 mum (95) control] and villous height [451 mum (20) BDL vs. 515 mum (18) sham vs. 559 mum (79) control] in jaundiced anima ls, compared with sham-operated and control animals (p<0.02, Mann-Whitney U -test), Electron microscopy revealed oedematous change associated with mild inflammation, disruption of desmosomes, and the formation of lateral space s between enterocytes, In addition, enterocytes showed vacuolation of their cytoplasm and mitochondrial swelling. Increased numbers of bacteria appear ed to be attached to the mucosa. These data provide evidence of physical di sruption of intestinal mucosa in jaundiced animals, most marked in the dist al ileum, Significant bacterial translocation occurs following bile duct li gation and this supports the hypothesis of gut barrier dysfunction with obs tructive jaundice. Copyright (C) 2000 John Wiley & Sons, Ltd.