Effect of Lactulose on Bacterial Translocation and Intestinal Adaptation in a Rat Model of Short Bowel Syndrome

BACKGROUND: It is frequently assumed that dietary nondigestible carbohydrates improve host resistance to intestinal infections by stimulating proliferation of the protective gut microflora. Therefore, the aim of this study was to define the effect of lactulose, a nondigestible carbohydrate, on bacterial translocation and intestinal adaptation in a rat model of short bowel syndrome (SBS). MATERIALS AND METHODS: Male Sprague-Dawley rats were divided into 3 experimental groups. Sham rats underwent bowel transection, SBS rats underwent 75% small bowel resection, and SBS-LAC rats underwent bowel resection and were treated with oral lactulose given in drinking water at a dose of 1.5 g x kg(-1) x day(-1) from the 3rd to the 15th postoperative day. Bacterial translocation (to mesenteric lymph nodes, liver, and portal and peripheral blood) and parameters of intestinal adaptation were determined on day 15. RESULTS: Treatment with lactulose did not change bacterial translocation, but decreased ileal mucosal weight (20%; P < 0.05), ileal mucosal DNA (2-fold decrease; P < 0.05) and protein (26%; P < 0.05), villus height in jejunum (21%; P < 0.05) and crypt depth in ileum (17%; P < 0.05), proliferation rates in jejunum (18%; P < 0.05) and ileum (15%; P < 0.05), and apoptotic index in jejunum (40%; P < 0.05) and ileum (36%; P < 0.05) compared with SBS animals. Bax expression was upregulated in SBS rats compared with control animals, but decreased following treatment with lactulose. CONCLUSIONS: In a rat model of SBS, oral lactulose does not improve bacterial translocation from the intestine, but inhibits intestinal adaptation.