發(fā)布時(shí)間：2018-03-01 06:12

  本文關(guān)鍵詞： Ⅱ型糖尿病 益生菌 腸道菌群 腸道粘膜屏障 短鏈脂肪酸　出處：《哈爾濱工業(yè)大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：隨著腸道菌群在糖尿病發(fā)病中的作用逐漸被揭示,益生菌在防治糖尿病中的作用備受學(xué)者關(guān)注。前期課題組從分離自西北牧區(qū)傳統(tǒng)發(fā)酵食品中的乳酸菌中,篩選出副干酪乳桿菌(Lactobacillus paracasei subsp.paracasei)G15和副干酪乳桿菌(Lactobacillus casei)Q14,初步證實(shí)副干酪乳桿菌G15和Q14對(duì)Ⅱ型糖尿病改善明顯,并發(fā)現(xiàn)腸道菌群在其中起著關(guān)鍵的調(diào)控作用。據(jù)此,本研究將進(jìn)一步揭示副干酪乳桿菌G15和Q14如何通過調(diào)控腸道菌群來發(fā)揮抗糖尿病的作用。采用高脂飲食結(jié)合鏈脲霉素建立Ⅱ型糖尿病(T2D)大鼠模型。實(shí)驗(yàn)共分為五組,分別為正常組(N)、糖尿病組(D)、二甲雙胍治療組(M)、G15治療組(G)和Q14治療組(Q)。整個(gè)實(shí)驗(yàn)歷時(shí)13周。采用ELISA法測(cè)定血清學(xué)相關(guān)指標(biāo);氣相色譜法測(cè)定短鏈脂肪酸;RT-PCR法測(cè)定腸道菌群、短鏈脂肪酸受體、緊密連接蛋白以及炎癥因子;免疫組織化學(xué)和HE染色分析腸道通透性和屏障功能。副干酪乳桿菌G15和Q14對(duì)T2D大鼠體重、糖耐量、胰島素抵抗以及血脂水平具有明顯的改善作用。T2D模型組大鼠的體重明顯下降,G15和Q14治療組顯著改善了糖尿病大鼠的體重減輕,二甲雙胍也顯示較明顯的改善作用。T2D大鼠的葡萄糖耐受能力顯著下降,各治療組葡萄糖耐量有了不同程度的改善。此外,G15和Q14還顯著改善了T2D引起的胰島素以及胰高血糖素的增加,改善了糖尿病大鼠胰島β細(xì)胞的受損癥狀。G15和Q14作用也緩解了Ⅱ型糖尿病大鼠模型血脂水平的增加。副干酪乳桿菌G15和Q14通過影響腸道菌群-短鏈脂肪酸-G蛋白偶聯(lián)受體通路來發(fā)揮抗糖尿病的作用。結(jié)果顯示:G15和Q14改善了大鼠的腸道菌群紊亂,增加了乙酸產(chǎn)生菌(乳酸菌、雙歧桿菌)和丁酸產(chǎn)生菌(柔嫩梭菌、普利沃菌)的含量,并增加乙酸和丁酸的含量。G15和Q14進(jìn)一步上調(diào)短鏈脂肪酸受體GPR43的表達(dá)而對(duì)GPR41受體無明顯作用,并且促進(jìn)GPR43下游胃腸激素GLP-1、PYY分泌。副干酪乳桿菌G15和Q14通過改善腸道粘膜結(jié)構(gòu)、緊密連接蛋白體系、粘膜通透性以及炎性指標(biāo)的炎性機(jī)制來發(fā)揮抗糖尿病作用。G15和Q14明顯降低了革蘭氏陰性菌(G-)、擬桿菌和腸桿菌的含量,并且伴隨著T2D大鼠血漿內(nèi)毒素(LPS)水平的降低。結(jié)腸粘膜病理學(xué)檢查發(fā)現(xiàn),糖尿病大鼠結(jié)腸上皮細(xì)胞連接破損、細(xì)胞部分被破壞,且杯狀細(xì)胞數(shù)量減少;G15和Q14可不同程度的修復(fù)腸粘膜屏障的受損。G15和Q14顯著改善了緊密連接蛋白(ZO-1、Occludin、Muc2)的表達(dá)。G15和Q14進(jìn)一步降低了糖尿病大鼠IL-1β、IL-6和IL-8的表達(dá)。綜上,副干酪乳桿菌G15和Q14能夠改善Ⅱ型糖尿病大鼠的糖耐量以及胰島素抵抗,其作用機(jī)制有如下兩方面:(1)以腸道菌群為核心,副干酪乳桿菌G15和Q14通過腸道菌群-SCFA-G蛋白偶聯(lián)受體通路發(fā)揮抗糖尿病的作用;(2)副干酪乳桿菌G15和Q14通過改善腸道粘膜結(jié)構(gòu)、緊密連接蛋白體系、粘膜通透性以及炎性指標(biāo)的炎性機(jī)制來發(fā)揮抗糖尿病作用。本研究進(jìn)一步解析G15和Q14通過腸道菌群改善T2D大鼠的深入機(jī)制,為益生菌用于糖尿病的防治奠定了理論基礎(chǔ);并從飲食角度防控Ⅱ型糖尿病提供了新思路。
[Abstract]:With the role in the pathogenesis of diabetes intestinal flora has been revealed, the role of probiotics in the prevention and treatment of diabetes in the concern of scholars. The research group from lactic acid bacteria isolated from traditional fermented food in the pastoral area of the northwest, screened L.paracasei (Lactobacillus paracasei subsp.paracasei) G15 and L.paracasei (Lactobacillus casei Q14) preliminary confirmed, L.paracasei G15 and Q14 on type II diabetes improved significantly, and found that the intestinal flora plays a key role. Therefore, this study will further reveal the pair of Lactobacillus casei strains G15 and Q14 how to play the anti diabetic effects by regulating intestinal flora by high-fat diet combined with. Streptozotocin to establish type II diabetes mellitus (T2D) rat model. Rats were divided into five groups, including normal group (N), diabetic group (D), metformin group (M), G15 treatment group (G) and Q14 treatment The treatment group (Q). The experiment lasted 13 weeks. Serum related indexes were measured by ELISA method; Determination of short chain fatty acid gas chromatography; RT-PCR method for determination of intestinal microflora, short chain fatty acid receptor, tight junction proteins and inflammatory factors; analysis of intestinal permeability and barrier function of immunohistochemistry and HE staining. Lactobacillus casei G15 and Q14 on T2D rats, glucose tolerance, insulin resistance and blood lipid levels has obvious improvement effect of.T2D model rats body weight decreased significantly, G15 and Q14 in treatment group significantly improved the body weight of diabetic rats reduced glucose tolerance, metformin also showed obvious improvement of.T2D rats in the treatment group significantly decreased glucose tolerance have different degrees of improvement. In addition, G15 and Q14 also significantly improved T2D induced by insulin and glucagon increased, improved rat pancreatic diabetes The island of beta cell damage symptoms of.G15 and Q14 to alleviate the increased level of serum lipid in rats model of type II diabetes. L.paracasei G15 and Q14 through the intestinal flora - short chain fatty acid -G protein coupled receptor pathway to play the anti diabetic effects. The results showed that G15 and Q14 improved intestinal disorders flora of rats, increase of acetic acid producing bacteria (Lactobacillus, Bifidobacterium) and butyrate producing bacteria (Clostridium leptum, Puliwo bacteria) content, and increase the expression of acetic acid and butyric acid content of.G15 and Q14 further increases in short chain fatty acid receptor GPR43 but had no obvious effect on the GPR41 receptor, and promote GPR43 downstream gastrointestinal hormone GLP-1, secretion of PYY. G15 and Q14 dry buttermilk bacillus by improving the structure of intestinal mucosa, tight junction protein system, and mucosal permeability in inflammatory markers of inflammatory mechanisms play anti diabetic effect of.G15 and Q14 decreased significantly. Gram negative bacteria (G-), the content of coli and Enterobacter, and accompanied by the plasma endotoxin in T2D rats (LPS). The decrease of the level of colonic mucosal pathological examination found that colonic epithelial cells in diabetic rats with damaged cells were damaged, and the decrease in the number of goblet cells; G15 and Q14 can be damaged and.G15 Q14 repair of intestinal mucosa barrier in different degree was improved obviously with the tight junction protein (ZO-1, Occludin, Muc2) on the expression of.G15 and Q14 further decreased in diabetic rats IL-1 beta, the expression of IL-6 and IL-8. In summary, dry weight and insulin resistance in G15 and L.CASEI Q14 can improve the glucose in type 2 diabetic rats resistance, the mechanism has the following two aspects: (1) to the intestinal flora as the core, L.paracasei G15 and Q14 play the anti diabetic effects of intestinal flora by -SCFA-G protein coupled receptor pathway; (2) the L.paracasei and Q14 by G15 Improve the structure of intestinal mucosa, tight junction protein system, play the anti diabetic effect of mucosal permeability and inflammatory index of inflammatory mechanisms. This study further mechanism further analytical G15 and Q14 through improving intestinal flora in T2D rats, as probiotics for the prevention and treatment of diabetes and laid a theoretical foundation; provides new ideas and Prevention from diet point of type II diabetes.

【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：R587.1
，

本文編號(hào)：1550737