Protective Effects Of Synbiotics In Mice With Acute Chemical Liver Injury And Its Research On The Regulation Of Intestinal Microbiota

Objective By exploring the protective effect of synbiotics in mice with acute chemical liver injury,the best synbiotics was found and analyzed for its regulatory effect on intestinal flora.Method 72 ICR male mice were randomly divided into 12 groups,each group with 6 mice,and the rearing environment was within the SPF barrier.Considering5%,15%and 20%wheat bran dietary fiber feeds as three different levels of factor A,namely A1,A2 and A3.Probiotic yogurt at doses of 10,20 and 30 m L/kg were treated as three different levels of factor B,namely B1,B2 and B3.For a total of 9 groups of two factors and three level（A1B1 group,A1B2 group,A1B3 group,A2B1 group,A2B2 group,A2B3 group,A2B3 group,A3B1 group,A3B2 group and A3B3 group）give a biam intervention with different combinations.The positive control group,model group and blank control group were given common feed.At the same time,the positive control group was given a compound solution of soft liver tablet.After 30 d,mice in all group except the blank control group were gavaged with 5m L/kg,and the blank control group gave the corresponding volume of corn oil solution.After 24h,mouse blood was collected by eye picking and their serum was isolated.Serum levels of alanine aminotransferase（ALT）,aspartate aminotransferase（AST）,superoxide dismutase（SOD）,malondialdehyde（MDA）,and lipopolysaccharide（LPS）were measured by ELISA.The liver,spleen,colon and ileum were collected and the organ index of the liver,spleen and colon were calculated.Observe the pathological transformation of the liver and ileum under the HE staining method.Liver tissues from A1B1 group,positive control group,model group and blank control group mice were collected to test the protein expression of liver COL 1 and TLR4.High-throughput sequencing of 16S DNA was used to detect the bacterial abundance and diversity of the feces of four groups of mice.Results 1.Protective effect of synbiotics in mice with acute chemical liver injury.（1）Effect of bibiotics on liver fibrosis.After acute infection with CCl₄,except for A1B1 group,the body mass of several mice was significantly reduced compared with the blank control and model group（P<0.05）.The liver index of A1B1group,A1B2 group,A2B1 group and A3B1 group was lower than that of the model group,and the spleen index of A2B1 group,A2B2 group and A2B3 group was significantly higher compared with the blank control group,model group and positive control group（P<0.05）.There was no significant difference in the colon index of mice（P>0.05）.Compared with the model group,A1B1 had complete structure and only few inflammatory cell infiltration,A2B2 group,A3B3 group and A3B3 group were severely damaged with massive inflammatory cell infiltration,and large unmetabolized CCl₄in A3B1 and A3B3 group.Compared with the blank control group,the ileum was disrupted in the A1B1 group.（2）The effect of bibiotics on liver function.The serum AST level in each synbiotics group was significantly reduced compared with the model and positive control groups.The serum SOD levels in both the A2B1 group and A2B3 group were lower than those in the model group and the positive control group.The serum MDA levels of A1B1 group,A1B2 group,A2B3 group,A3B1 group and A3B2 group were all lower than the model group（P<0.05）,and the serum LPS levels of A1B1 group,A2B1group,A3B1 group and blank control group were significantly lower than those of the model group（P<0.05）.2.Regulation of liver damage and intestinal microbiota by A1B1complex.（1）Protein expression levels of COLI and TLR 4 in the liver.The hepatic COLI and TLR4 protein levels in A1B1 group were significantly lower than those in the model group（P<0.01）,and the serum LPS level in A1B1 group was significantly lower than that in the model group（P<0.05）.It is proved that A1B1 protects the liver.（2）Effect of A1B1group intervention on the diversity of intestinal flora in mice with liver fibrosis.Compared with the model group,theα-diversity of A1B1 mice increased（P<0.05）and theβdiversity was significantly higher than that of the blank control group and model group.（3）Effect of A1B1 synthesis group intervention on the composition of intestinal microbiota in mice with liver fibrosis.At the phylum level,the relative abundance of Firmicutes and Proteobacteria was significantly higher in the A1B1 group than in the model group（P<0.05）.At the class level,the abundance of Epsilonproteobacteria,Deltaproteobacteria,and Bacilli was significantly higher in A1B1 group than in the blank control group（P<0.05）.At the family level,Ruminococcaceae,Helicobacteraceae and Desulfovibrionaceae abundance was significantly higher in A1B1 group mice than in the blank control group（P<0.05）.At the genus level,seven A1B1 group had a higher relative abundance than the model group（P<0.05）The linear discriminant analysis of LEf Se showed that the microbial groups in A1B1 group was significantly higher than the model group.（4）Effect of A1B1 group biointervention on co-expression network and function of intestinal microbiota in mice with liver fibrosis.By Bug Base analysis,Proteobacteria plays a role in Biofilm Forming,Pathogenic,Mobile Element Containing Aerobic and Oxidative Stress Tolerant function.Proteobacteria Was the most abundant in the blank control group,followed by the positive control group and the A1B1 group.There were strong associations between the bacterial species abundance composition and their functional abundance composition of the four samples and strong similarity between the A1B1 group and the positive control group.The Faprotax functions of the four samples are mainly chemoheterotrophy and oheterotrophy,except besides the model group,the other three groups have the functions of respiration＿of＿sulfur＿compounds and sulfate＿respiration.Conclusion The syngenite composed of wheat bran dietary fiber combined with probiotic yogurt used in this study has a certain ability to protect the liver of mice with acute chemical liver injury.The A1B1 group of 5%wheat bran dietary fiber combined with 10m L/kg probiotic yogurt had the best effect,and the mechanism may be related to the regulation of the gut-liver axis.