Study Of Screening In Vivo And In Vitro Of Two Strains Lactobacilli With The Capability Of Cholesterol-reducing And Their Relative Mechanism Of Cholesterol-reducing

ObjectiveTo screen the strains with the capability to reduce cholesterol from the potential target bacteria isolated by stool samples of healthy adults and identify them.MethodsWe screen the potential target bacteria through modified cholesterol MRS medium as the screening model, and preliminary identify the strains with relative strong capability to cholesterol-reducingResultsScreened out four strains with the 30% or more capability to cholesterol-reducing, with degradation rates M7-5 44.7%, M2-1 34.2%, M10-2-8 32.5%, and MM1-16 32.4% respectively. Identify M7-5 and M2-1 and M7-5 is Lactobacillus fermentum, M2-1 is Lactobacillus plantarum.ConclusionM7-5 and M2-1 had strong capability to cholesterol-reducing in vitro, The result of identification shows that M7-5 and M2-1 were Lactobacillus fermentum, and Lactobacillus plantarum., respectively andwe need Further Study of them to apply them to the animals in vivo. ObjectiveTo observe the effect of two strains of lactobacilli on the Cholesterol metabolism of the male Sprague-Dawley rats fed with high-fat diet and to evaluate their efficacy and safety on lowing cholesterol levels, so as to provide support for screening bacteria that could reduce cholesterol.Method40 SD rats were randomly divided into 4 groups, K, E, F and I group. K group was normal group fed with the normal diet, E group was interfered with high fat diet and lactobacillus M2-1, F group was interfered with high fat diet and lactobacillus M7-5.Ⅰgroup was model group, interfered with high fat diet only. All rats were sacrificed in the 6th week, then the levels of serum lipids, serum total bile acids, total cholesterol, liver lipids, fecal lipids, weight gain, Lee's index, liver histopathology, serum glutamic-pyruvic transaminase and other index were detected.Results1. Interfered with lactobacilli, levels of serum TC, TG and LDL-C in the E and F group were lower compared with the model group, and higher compared with the normal group. The difference was significant. Effect of the M7-5 was the best, the difference was significant. 2. In the 4th and 6th week, levels of serum bile acid in the E group was higher compared with the normal group (P>0.05), and was lower compared with the model group(P<0.05).3. Levels of fecal bile acids and cholesterol in the model group were higher compared with the normal group(P<0.05), the difference was significant. Bile acid Level in the E group was higher compared with the model group. Cholesterol Level was lower compared with the normal group. The difference was significant.4. Lee's index of model group was higher compared with the normal group (P<0.05). It was lower in the model group and higher in the normal group compared with Lactobacillus E and F group. Especially in the 6th week, difference was significant between the F and I group (P <0.05).5. weight gain daily in the model and Lactobacillus groups was higher compared with the normal group, difference was significant; From the 6th week, weight gain in the F group decreased. It was lower compared with the model group (P<0.05). Difference was significant.6. Adipose degeneration was very obvious in the model group and very slight in the Lactobacillus E and F groups with the method of HE staining of fatty liver7. Serum bile acid in the model group were increased, but there was no difference between the model and other groups. Conclusion1. Feeding the SD rats continuously with modified improvement compounding of high-fat diet for 6 weeks could successfully induce model of hyperlipoidemia, especially hypercholesterolemia.2. Two strains of Lactobacillus M7-5 and M2-1 could low the level of hyperlipemia in the SD model.M7-5 had a better effect.3. The possible mechanism of the two strains of Lactobacillus lowerng the hyperlipoidemia might be decreasing the deposition of liver lipid and increasing the excretion of fecal fat. Their mechanism might not be exactly the same. The former might be mostly increasing the excretion of the fecal cholesterol and the latter increasing the excretion of the fecal bile acid. ObjectiveInvestigate possible affection mechanism of SD rats alimentary hyperlipoidemia by two lactobacillusMethodsTest animals,group,group and intervention are same as the 2nd chapter, rats were executed after the 6th week, specimen of liver and ileal mucous membrane mucosae were kept to test expression of liver nuclear receptor FXR and cell surface receptor ABCA1 and ABCG5 mRNA, and expression of ileal mucous membrane mucosae LXRa,ABCA1 and ABCG5.Results1. Liver receptor FXR and LXRa, ileal mucous membrane mucosae LXRa, ABCA1 and ABCG5 in hyperlipoidemia group were obvious different with normal group (P<0.05), but liver ABCG5 were not obviously up-regulated.2. In E group of lactobacillus, liver receptor FXR were obviously down-regulated and LXRa were obviously up-regulated, ileal mucous membrane mucosae surface receptor ABCG5 were up-regulated in liver tissue.3.In F group of lactobacillus, liver nuclear receptor FXR were obviously down-regulated and LXRα,ABCG5,ileal mucous membrane mucosae surface receptor LXRα,ABCA1 and ABCG5 were obviously up-regulated with statistics significance compared to hyperlipoidemia group (P<0.05)Conclusion1. Lactobacillus fermentum M7-5 and Lactobacillus plantarum M2-1 can degrade serum cholesterol in high fat diet SD rats.2.Affection target of Lactobacillus fermenti M7-5 and Lactobacillus fermenti M2-1 possible related with hepatic tissue and receptors in ileal mucous. the fronter depressed FXR expression of liver and up-regulated expression of LXRα,ABCA1 and ABCG5 in mucous tissue in liver and ileal which leads to the enhancing of cholesterol excretion. the later obviously depressed FXR expression of liver and up-regulated expression of LXRa in liver and ABCG5 in ileal mucous membrane which enhance the synthesis of bile acid and cholesterol excretion to down-regulate cholesterol...