The protective effect and molecular mechanism of live combined Bifidobacterium and Lactobacillus tablets against acute liver failure in mice

Abstract

Objective To investigate the mechanism of live combined Bifidobacterium and Lactobacillus tablets in acute liver failure (ALF) treatment. Methods Ten mice were injected intraperitoneally with 3.0 g/kg D-galactosamine to establish the model of ALF and treated with live combined Bifidobacterium and Lactobacillus tablets. Protein levels of Jagged1, Notch1, Notch intracellular domain (NICD), Hes5 and the mRNA expressions of Jagged1, Notch1, Hes5 were measured via Western blot and real time-polymerase chain reaction (PCR), respectively. The protein level of CD68 was detected by immunohistochemical staining method. Meanwhile, serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), interleukin (IL)-10, high mobility group protein B1 (HMGB1) and plasma lipopolysaccharide (LPS) were measured. Moreover, model group and control group were also established with 10 mice each. In vitro, RAW264.7 cells were cultured with normal mice plasma, plasma of ALF mice and plasma of treated mice, respectively. Real time-PCR and Western blot were used to determine the mRNA expressions of Jagged1, Notch1, Hes5 and proteins levels of Jagged1, Notch1, NICD, Hes5. The levels of IL-10, HMGB1 and LPS in the supernatant of RAW264.7 cells were detected as well. The total significant differences among groups were compared by one way ANOVA, and q test was used to evaluate the significance of subgroup differences. Results The levels of serum ALT, AST, HMGB1, IL-10, plasma LPS, and the expressions of Jagged1, Notch1, NICD, Hes5, CD68 were higher in ALF model group than control group (all P<0.01). Compared with the ALF model group, all of these indexes could be improved in mice with live combined Bifidobacterium and Lactobacillus tablets (HMGB1: [82.6±9.7] μg/L vs [101.9±12.4] μg/L, q=6.36, P<0.01; IL-10: [3 183±769] pg/mL vs [4 628±842] pg/mL, q=6.79, P<0.01; plasma LPS: [7.40±0.92] EU/mL vs [11.80±0.89] EU/mL, q=18.81, P<0.01; Jagged1 mRNA: 5.55±0.71 vs 7.63±1.41, q=7.22, P<0.01; Jagged1 protein: 0.56±0.07 vs 0.71±0.07, q=7.20, P<0.01; Notch1 mRNA: 3.66±0.67 vs 7.10±0.66, q=20.06, P<0.01; Notch1 protein: 0.38±0.08 vs 0.66±0.11, q=9.57, P<0.01; NICD protein: 0.47±0.05 vs 0.76±0.07, q=12.68, P<0.01; Hes5 mRNA: 3.94±0.68 vs 7.95±0.71, q=22.40, P<0.01; Hes5 protein: 1.04±0.12 vs 1.20±0.07, q=5.61, P<0.01; CD68 protein: 5 180±610 vs 7 685±417, q=16.38, P<0.01). And the differences were statistically significant. After RAW264.7 cells cultured with the plasma of ALF model mice, the levels of HMGB1, IL-10 and LPS in the supernatant and the expressions of Jagged1, Notch1, NICD and Hes5 in cells were increased, whereas if RAW264.7 cells were cultured with the plasma of treated mice, indexes mentioned above were significantly decreased (all P<0.01). Conclusions Live combined Bifidobacterium and Lactobacillus tablet could prevent the occurrence and development of ALF by decreasing the plasma level of LPS, inhibiting the activation of Notch signaling pathway in macrophages and reducing the secretion of HMGB1 and IL-10. Key words: Liver failure, acute; Lipopolysaccharides; Notch signaling pathway; HMGB1 protein; Interleukin-10