Protective effects of lactulose on the intestinal tract barrier in rats with portal hypertension

Objective To investigate the effects of lactulose on the intestinal epithelial tight junction, bacterial translocation (BT) and intestinal endotoxemia in rats with portal hypertension. Methods Animal models of portal hypertention were established in 50 male Sprague-Dawley rats by subcutaneously injection of carbon tetrachloride (CCl4). Then the rats were randomly divided into 3 groups: ① treatment group (T group), received lactulose syrup (5 mL/kg) feeding twice daily for 7 days, ② control group(C group), received glucose feeding only, and ③ portal hypertension group (M group) as the control group. After 8 days, all rats were sacrificed. Whole blood, liver, splenic, and kidney tissues, together with the mesenteric lymph nodes were collected for germ culture and bacterial translocation detection. The ultrastructure of intestinal epithelial tight junction and the intestinal villi were observed by electron microscopy. The transmembrane binding protein (occludin) expression in the terminal ileum was detected by immunohistochemistry assay. The plasma endotoxin was also determined. Results The translocation of bacteria was found in groups M and C. Group T demonstrated improved liver function. The plasma endotoxin in group T was 0.18±0.09Eu/ml, which was significantly lower than that of groups C (0.35±0.07Eu/ml) and M (0.46±0.08Eu/ml, P0.01). The occludin expression was decreased in groups M and C than that in group T (P0.01). Conclusions Lactulose lavage could induce occludin expression, maintain the intestinal epithelial tight junction, reduce the bacterial translocation and diminish the endoxemia. This study might provide a new rationale in the treatment of cirrhosis patients with portal hypertension.