Probiotic Function And Underlying Mechanism Of Lactobacillus Plantarum NCU116

Probiotics have been defined as “live microorganisms which, when administered in adequate amounts, confer a health benefit on the host”. Probiotics have several kinds of functions, such as regulating intestinal flora, alleviating metabolic syndrome and immunomodulatory. Lactobacillus plantarum NCU116 was recently isolated from pickled vegetables. Previously reports have showed that this bacterium is characterized with good performance in vitro. However, the character of the probiotic in vivo is unclear. The present study was to investigate the effects of L. plantarum NCU116 on intestinal flora, constipation, hyperlipidaemia, non-alcoholic fatty liver disease, inflammatory bowel disease, diabetes; and serum metabolomics methods were developed to investigate the effect of metabolites of L. plantarum NCU116 on hyperlipidaemia and diabetes. The main conclusions obtained in this dissertation are summarized as follows:(1) Mice were randomly divided into four groups and orally administrated saline and three doses of L. plantarum NCU116 groups(NCU116-L, 107 CFU/m L; NCU116-M, 108 CFU/m L; NCU116-H, 109 CFU/m L; respectively) for five weeks. Compared with the normal group, Lactobacillus, Bifidobacterium, short chain fatty acids were increased in the groups that received L. plantarum NCU116. In addition, the probiotic reduced the oxidative stress and proinflammatory factor in serum.(2) This part of study examined the effects of L. plantarum NCU116 on loperamide-induced constipation in a mouse model. Loperamide was injected subcutaneously to induce constipation. Animals were divided to five groups: normal group, constipation group, constipation plus three doses of L. plantarum NCU116 groups(NCU116-L, 107 CFU/m L; NCU116-M, 108 CFU/m L; NCU116-H, 109 CFU/mL; respectively). Mice were treated with the probiotic for 15 days to assess the anti-constipation effects. Fecal parameters, intestinal transit ratio and the production of fecal short chain fatty acids, histological of colon and immunohistochemical in colonic cells of Cajal(ICC) by c-kit were all improved in L. plantarum NCU116 treated mice as compared to the constipation group. These results demonstrated that L. plantarum NCU116 enhanced gastrointestinal transit and alleviated loperamide-induced constipation.(3) The cholesterol-lowering effect of L. plantarum NCU116 on lipid metabolism of rats fed on a high fat diet was investigated. Sprague-Dawley rats were randomly divided into normal diet(ND) group, high fat diet(HFD) group, HFD plus L. plantarum NCU116 groups with two different doses(NCU116-L, 108 CFU)/mL; NCU116-H, 109 CFU/mL). After treatment for 5 weeks, L. plantarum NCU116 had the potential ability to regulate lipid metabolism levels, morphology of pancreas and adipose tissues. In addition, the bacterium significantly improved gene expression of low-density lipoprotein(LDL) receptor and cholesterol 7α-hydroxylase(CYP7A1). These results suggested that L. plantarum NCU116 was able to alter lipid metabolism and reduce the cholesterol level, in particular, in the rats on a high fat diet through regulating gene expression of key factors relating to LDL receptor and CYP7A1.(4) The effects of L. plantarum NCU116 on liver function, oxidative stress and lipid metabolism in rats with high fat diet induced non-alcoholic fatty liver disease(NAFLD) were studied. Treatment of L. plantarum NCU116 for 5 weeks was found to restore liver function, liver morphology and oxidative stress in rats with NAFLD, and decrease the levels of fat accumulation in liver. In addition, the bacterium significantly reduced endotoxin and proinflammatory cytokines, and regulated bacterial flora in the colon and the expression of lipid metabolism in the liver. These results suggested that downregulating lipogenesis and upregulating genes expression related to lipolysis and fatty acid oxidation were involved in the beneficial effect of L. plantarum NCU116 on NAFLD.(5) A metabolomics method based on ultraperformance liquid chromatography quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF/MS) was developed to investigate the metabolites of L. plantarum NCU116 on serum from high fat fed rats. With t test unpaired analysis, a good separation of PCA, PLS-DA and HCA of four groups was achieved. 13 potential biomarkers, including spermidine, pantothenic acid, indoleacrylic acid, indole, 5-hydroxy indole acetaldehyde, glycocholic acid, biliverdin IX, glycolic acid, L-leucine, 2-phenylethanol glucuronide, taurocholic acid, 2-arachidonoylglycerol, pregnanediol-3-glucuronide have been identified in serum samples from high fat fed rats. In additoion supplement of L. plantarum NCU116 regulated the levels of indoleacrylic acid, glycocholic acid, glycolic acid, taurocholic acid, 2-arachidonoylglycerol, pregnanediol-3-glucuronide, and pathways of lipids, glucose and lipoprotein to alleviate hyperlipidaemia.(6) Effect of carrot juice fermented with L. plantarum NCU116 on 2, 4, 6-trinitrobenzenesulfonic acid-induced inflammatory bowel disease(IBD) in mice was studied. Mice were randomly divided into five groups: normal, IBD, IBD plus L. plantarum NCU116(NCU), IBD plus fermented carrot juice with L. plantarum NCU116(FCJ) and IBD plus non-fermented carrot juice(NFCJ). Treatments of NCU and FCJ for 5 weeks were found to favorably regulate oxidative stress, proinflammatory factor, histological of colon; and increase body weight, short chain fatty acids compared with the IBD group. In addition, compared with the NFCJ group, the function of NCU and FCJ groups closely related to the supplement of L. plantarum NCU116.(7) Effect of carrot juice fermented with L. plantarum NCU116 on high fat and low-dose streptozotocin(STZ)-induced type 2 diabetes in rats was studied. Rats were randomly divided into five groups: non-diabetes mellitus(NDM), un-treated diabetes mellitus(DM), DM plus L. plantarum NCU116(NCU), DM plus fermented carrot juice with L. plantarum NCU116(FCJ) and DM plus non-fermented carrot juice(NFCJ). Treatment of NCU and FCJ for 5 weeks were found to favorably regulate blood glucose, hormones and lipid metabolism in the diabetic rats, accompanied by an increase in short chain fatty acids(SCFA) in colon. In addition, NCU and FCJ restored the antioxidant capacity, morphology of pancreas and kidney, and up regulated mRNA of low-density lipoprotein(LDL) receptor, cholesterol 7α-hydroxylase(CYP7A1), glucose transporter-4(GLUT-4), peroxisome proliferator-activated receptor-α(PPAR-α), and peroxisome proliferator-activated receptor-γ(PPAR-γ). These results for the first time demonstrated that L. plantarum NCU116 and the fermented carrot juice had the potential ability to ameliorate type 2 diabetes in rats.(8) A novel analysis method based on UPLC-Q-TOF/MS was developed to investigate the effects of L. plantarum NCU116 and its fermented carrot juice on the metabolites of sera from type 2 diabetic rats. With t test unpaired analysis, a good separation of PCA and PLS-DA of five groups was achieved. Eight potential biomarkers were identified in serum samples from type 2 diabetic rats. Biological pathways and processes were significantly changed by NCU and FCJ treatments. In addition, the NCU and FCJ groups showed good clustering than other groups, thus, the possible mechanism by which NCU and FCJ ameliorate type 2 diabetes in rats may be related to the action of L. plantarum NCU116 in the supplement.