Screening of Lactic Acid Bacteria with Glucose Homeostatic Effects in FL83B Hepatocytes

Autor: TENG,YI-LIN, 滕逸林
Rok vydání: 2016
Druh dokumentu: 學位論文 ; thesis
Popis: 104
With the increasing patient population year by year, diabetes mellitus has became one of top ten leading causes of death in Taiwan. The risk is closely related to factors such as changes of lifestyle, lack of exercise and improper diet. Studies also show that maintaining the balance of microbiota in intestinal can reduce the incidence of type 2 diabetes mellitus, whereas lactic acid bacteria (LAB) are the most important species. Literatures have proved LAB or it’s fermented products have physiological activities in modulating immune system function, blood pressure, blood sugar, lipid and improving fatness. However, few LAB products with blood sugar regulation activity are available, thus the aims of this study are to investigate the probiotics characteristics of the isolated LAB, and to understand their in vitro mechnism and impact on glucose homeostasis.LAB strains isolated from fermented foods, vegetables and infant feces were preliminarily verified by their catalase activities, Gram staining and curd tests. After further typing by genomic DNA sequencing, the intestinal epithelial cell adhesion, acid tolerance and bile salts tolerance of the isolated strains were evaluated.The sequencing results indicated these isolated LAB strains were mostly Lactobacillus and Weissella spp.. With further detection in preserving glucose homeostasis, many LAB strains have revealed notable inhibition in α-glucosidase activity with their culturing media up to 90%.The results confirmed that none of 9 LAB strains have shown proliferation inhibition when murine FL83B hepatocytes were treated with their culturing media. Glucose analogues (NBDG) intake analyses revealed that FL83B hepatocytes treated for 12 and 24 hours with culturing media have shown efficient intakes, therefore all subsequent assessments were peroformed at these two time points.Treatments with LAB culturing media have enhanced the glycogen syntheses in FL83B cells under both normal and high glucose-induced resistance conditions. Under certain concentration of LAB culturing media, improved phosphorylation of AKT in murine FL83B hepatocytes when probing insulin signaling by Western blotting. The activation extents were elevated with the treatments of LAB culturing media as shown in cellular insulin signaling investigations analyzed with Western blots of AKT phosphorylation. To sum up the results mentioned above, the culturing media of the isolated LAB’s in this study have imposed regulation effects on hepatocyte FL83B at all levels in turn to maintain the glucose homeostasis.
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