The Changes Of Liver-intestinal Axis Function Promote The Pathogenesis Of Nonalcoholic Fatty Liver Disease

Objective：To establish the nonalcoholic fatty liver model,and observe the dynamiclevel of liver steatosis and changes of intestinal flora in the model group fed by highfat diet, and other groups when given antibiotics or low calorie fat diet intervention.MethodsPart1: to determine the intestinal flora is the risk factor of the process of NAFLD.Seven-two male SD rats were randomly divided into FD group, the bacteriainhibition(KY) group, and the control(ND) group.The control group was feedby ordinary diet and drank normal water.FD group was feed by high fat anddrank normal water to form NAFLD model,and KY group was also feed byhigh fat diet, while drinking antibiotic solution.The feed lasted for4weeks.Then the six rats in all the groups respectively were put to execution, taking apiece of liver’s and ileocecal tissue to make conventional pathology HEstaining,and.ileocecal feces were collected to extract bacteria DNA, accordingto the16SrRNA sequence to measure the number of fourbacterias,(bifidobacterium,lactobacillus, enterococcus bacteroidetes andenterobacterium)every week. The level of serum and triglyceride (TG),cholesterol (TC), serum high-density lipoprotein (HDL), low densitylipoprotein (LDL) content, and serum AST, ALT were measured by enzymeratio method.FIAF expression level was detected by immunohistochemical andRT-PCR. Part2: to evaluate the effect of different treatments of NAFLD,including thelow-fat diet and antibiotics intervertion.Ninety-six SD rats were selected and fed by high fat diet to estabishedNAFLD model,lasting for4weeks,then were randomly divided into NAFLDgroup, the antibiotics restriction group and the normal control group. Thebehavior of all the groups was detected qod. Six rats of every group were putto execution.Then all the methods of specimen collection and processingwere the same as Part1.ResultsPart1:The food intake and activity in fixed time of the group of FD rats were lower thanthe groups of ND and KY,while the cumulative energy intake of FD wassignificantly higher.The weight of all the groups was increasing by feeding alongwith the times going on, especially the group of FD,which shows the significantdifferences between FD and ND.but it shows no differences between KY andND,which increases slowly. To every groups at different times in addition to theHDL, ALT, comparing with different groups,the index of serum or livermetabolism of glucolipid shows FD group> KY group> ND group. The data ofFD group rats were significantly higher than the rest of the two groups after4weeks’ feeding.There was no differences in the serum HDL and ALT among thedifferent groups (P>0.05); The results of HE shows that the steatosis of livertissue of FD group become more serious as times goes on, with many sizes ofround fat vacuoles and inflammatory cell infiltration in local lessions.The group ofthe preprocessing group of antibiotics shows lower pathological scores than FDgroup and have the statistical difference (P <0.05), until to the fourth week withfeeding.3) All the groups shows the positive correlation between the expressionof FIAF in liver tissue and the severity of the steatosis test by both PCR andIHC.,and the higher expression of group FD,comparing with the group KY at thefourth week (P <0.05).4) The group of FD presents a trend of gradual decline ofthe number of lactobacillus and bifidobacterium and shows lower relativelyquantitative of them compared with the normal group, it had the statisticdifference until three or four weeks feeding (P <0.05);while the Enterococcus increased from the second week;There was no obvious statistical significanceamong the whole groups about enteric bacilli.The level of KY group wasinhibited,and significantly lower than ND and FD group.Part21)The NAFLD group,which maintained high fat diet, the weight and theaccumulated energy intake of rat,was higher than the group of ND and XZ,whilethe numbers of independent activities are on the opposite.The level of XZgroup showed higher than that of the other three groups. After intervention byantibiotics,,the index of serum or liver metabolism of glucolipid showed a slowtrend of increase in group KH and presents obvious lower than the group NAFLDat the tenth week(P>0.05),except HDL, ALT. In addition,all the indexs declineafter food inhibition2) The steatosis could be reversed in group XZ,and showslower than the normal group,although it is slow increasing in group KH whenstained by HE.3) The results of immunohistochemistry and rt-pcr showed thathigher expreesion of FIAF in group of NAFLD and KH,especially the groupNAFLD,while the lowest in group XZ.3) By treatment with antibiotic, theexpression of intestinal floras was inhibited in group KH.the number oflactobacillus and bifidobacterium presented a trend of gradual decline in NAFLDgroup,and increases obviously at eighteen and tenth week.(P <0.05), the group ofXZ shows the opposite. trends increase.The expression of Enterococcus wasdecreasing gradually in NAFLD while increasing in XZ group. Both of themshow the statistically significant difference (P <0.05).Conclusion:The intestinal micro ecology was a crucial risk factor for the pathogenesis ofNAFLD,while treating with low calorie diet and antibiotics could alleviateNAFLD by adjusting the intestinal microecological.Those provided a newprevention of NAFLD through the direction of microecological.