Modulation of the Colonic Bacterial Flora Affects Differently Bacterial Translocation and Liver Injury in an Acute Liver Injury Model

Abstract

Objective: To evaluate the effects of the administration of different bacterial strains on the extent of liver injury and bacterial translocation in an acute liver injury model. Design: Experimental study. Setting: University hospital, Sweden. Subjects: Sprague-Dawley rats. Interventions: Six different bacterial strains (Bacteroides fragilis ATCC 25285^T, Enterococcus faecium No.1, Enterococcus faecium No.2, Escherichia coli F131, Lactobacillus plantarum DSM 6595, and Bifidobacterium longum ATCC 15707^T) were administered rectally daily, for 8 days. Liver injury induced on the 8th day by intraperitoneal injection of D-galactosamine (1.1 g/kg BW). Main outcome measures: Samples were collected 24 h after the liver injury. Liver enzymes and bilirubin serum levels, bacterial translocation (to arterial and portal blood, liver and mesenteric lymph nodes), and intestinal microflora were evaluated. Results: The incidence of bacterial translocation to arterial and portal blood decreased significantly in Lb. plantarum and Bd. longum groups compared to the liver injury. The number of translocated bacteria to portal blood decreased in Bd. longum, Lb. plantarum, Ent. Faecium No.1, Ent. Faecium No.2 groups compared to E. coli group. In the arterial blood it decreased in Lb. plantarum and B. longum groups compared to Bact. fragilis and E. coli groups. Bacterial translocation to the liver increased significantly in E. coli group compared to liver injury, while it decreased in Lb. plantarum and Bd. longum groups compared to liver injury, Bact. fragilis and E. coli groups. In mesenteric lymph nodes, bacterial translocation decreased in Lb. plantarum group compared to liver injury, Bact. fragilis and E. coli groups. The release of liver enzymes increased in Bact. fragilis group compared to all the other groups. It decreased in Lb. plantarum compared to liver injury, Bact. fragilis and E. coli groups. Conclusion: Modulation of the intestinal microflora by different bacterial types has different effects on the extent of liver injury and bacterial translocation. Administration of Bact. fragilis and E. coli increased bacterial translocation and the extent of the liver injury. Administration of Lb. plantarum and Bd. longum reduced bacterial translocation, while Lb. plantarum reduced hepatocyte damage indicated by decreased liver enzyme release.