| AIM: The aim of the present study was to confirm the bacterial translocation (BT) in rat model of acute liver failure (ALF), to explore the correlation between lipopolysaccharide (LPS) and Toll-like receptor 4 (TLR4), furthermore, to evaluate the preventive and curative effect of montmorillonite (smecta) on the situation.METHODS: Fifty rats without ampicillin-resistant bacteria growth in the stool culture were randomly divided into five groups: normal control group (group A), normal saline control group (group B), ALF model group (group C), prevention group (group D), and treatment group (group E), with 10 rats in each group. D(+)-Galactosamine hydrochloride (D-GalN)(2.2g/kg) was injected into the abdominal cavity of rat to induce ALF. Escherichia coli JM109 labeled with enchanced green fluorescent protein (EGFP) was administrated for 3 days to track BT. Simultaneously, the rats received administration of smecta (0.6g/kg) for 6 times to improve this situation. Blood was collected for measuring liver function, endotoxin and TLR4 expression. Representative tissue specimens from liver, spleen and the mesenteric lymph nodes (MLN) were aseptically harvested for bacterial identification by agarose gel electrophoresis (AGE), laser scanning confocal microscopy (LSCM) and flow cytometry (FCM). All statistical analyses were performed using the Statistical Program for Social Sciences (SPSS 13.0). All data were expressed as means±SD. Comparisons between multiple groups were performed with one-way ANOVA followed by LSD-t test. If the data were not normally distributed, the Kruskal–Wallis H test was performed followed by Mann–Whitney U test, and Bonferroni revise. Differences at P < 0.05 were considered statistically significant.Results: It was found that BT occurred in rat model of ALF with direct and indirect evidence, accompanied by the increased concentration of LPS and TLR4 expression level. The detection of endotoxin in 100μl of serum was 34.37±5.0, 33.44±4.1, 53.35±5.0, 41.46±5.2 and 47.30±7.9 (ng/l) respectively in group A, B, C, D and E. No statistical difference was observed in LPS between normal control group and normal saline control group (P=0.71). Compared with normal control group, LPS in ALF model group, prevention group and treatment group was significantly higher (P<0.01). LPS in prevention group and treatment group was lower than that in model group (P<0.05). Additionally, LPS was lower in prevention group than in treatment group (P<0.05). The expression of TLR4 on the surface of monocytes by FCM in group A, B, C, D and E was 328.79±31.3, 347.83±29.9,554.49±40.6,478.24±31.5 and 522.06±29.1 respectively. No statistical difference was observed between normal control group and normal saline control group (P=0.20). Compared with normal control group, TLR4 expression in model group, prevention group and treatment group was significantly higher (P<0.001). It in prevention group and treatment group was lower than that in ALF model group (P<0.05). Additionally, it was lower in prevention group than in treatment group (P=0.004). Besides, no significant difference was observed in geometric mean fluorescence (GMF) of GFP in the tissues between normal control group and normal saline control group (P>0.05). Compared with normal control group, GMF of GFP in the tissues in ALF model group, prevention group and treatment group was significantly higher (P<0.05). It in the tissues in prevention group and treatment group was lower than that in ALF model group (P<0.05). In addition, it in the tissues was lower in prevention group than in treatment group (P<0.05).Conclusion: BT has been confirmed in rat model of ALF, accompanied by the increased concentration of LPS parallel with expression of TLR4. It is concluded that intestinal intervention with smecta can ameliorate the situation of BT, moreover, its preventive effect is more satisfactory than its therapeutic effect.
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