乳酸菌抗氧化性及其对小鼠结肠氧化还原状态调节的研究

发布时间：2018-02-10 17:48

本文关键词： 乳酸菌氧化应激铁结肠炎肠道菌群肠屏障　出处：《江南大学》2009年硕士论文　论文类型：学位论文

【摘要】： 肠道是机体最容易受到自由基攻击而发生氧化损伤的部位,乳酸菌可直接在肠道发挥抗氧化作用成为有前景的抗氧化剂。本文以Fe2+/VitC诱导大鼠肝匀浆脂质过氧化为模型,分析29株乳酸菌抑制脂质过氧化的作用(MDA抑制率),结果表明乳酸菌的抗氧化活性呈菌株依赖性。测定乳酸菌清除亚铁离子能力、胞内超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)酶活,分析乳酸菌的抗氧化机制,乳酸菌抗脂质过氧化作用与这三者的相关系数r分别为0.407、0.559、0.455(P0.01),但不同乳酸菌可以不同的机制为主实现抗氧化。本文进一步建立模拟结肠环境的体外模型,以此研究抗氧化乳酸菌对结肠食糜羟自由基含量及细菌构成的影响。乳酸菌L. paracasei Fn032、L. rhamnosus GG (LGG)、L. sp Fn001(抗脂质过氧化能力分别为95.31%、89.93%、29.41%)可不同程度减少体系中.OH含量,抑制大肠杆菌和肠球菌的增殖,其中Fn032、LGG作用显著(P0.05)。高铁日粮(铁含量为0.07%)饲喂小鼠,并分别灌胃乳酸菌Fn032、LGG、Fn001109CFU/天,研究不同抗氧化能力的乳酸菌对高铁引起的结肠食糜及肠粘膜氧化损伤的缓解。结果表明Fn032、LGG、Fn001可不同程度降低结肠食糜亚铁离子含量、结肠ROS、MDA水平;提高小鼠结肠T-AOC能力、CAT、SOD和GSH-Px活性;抑制肠道大肠杆菌、肠球菌等病原菌过度增殖,保护肠粘膜的屏障功能,降低肝脏内毒素水平。其中Fn032、LGG作用显著。论文最后建立DSS诱导小鼠肠炎模型,并以LGG、L. acidophilus Fn037和L. plantarum Fn003(体外抗脂质过氧化能力分别为89.93%、82.41%、37.40%)干预,研究不同抗氧化能力乳酸菌对炎症反应引起的结肠粘膜氧化损伤的缓解。结果表明LGG、Fn037能较好地抑制肠炎引起的粘膜氧化损伤,显著降低粘膜MPO活性、ROS和MDA水平,提高结肠粘膜总抗和各抗氧化酶含量(P0.05),维持肠道正常菌群,保护肠粘膜,显著降低肝脏内毒素水平(P0.05),Fn003效果不显著。抗氧化乳酸菌具有产SOD、GSH-Px或具有清除Fe2+的能力,这些乳酸菌可以改善小鼠结肠食糜及粘膜氧化还原状态,缓解肠道氧化应激。抗氧化作用可能是某些乳酸菌发挥益生作用的机制之一,具有抗氧化作用的乳酸菌在食品和医疗领域具有应用潜力。
[Abstract]:Intestinal tract is the most vulnerable site of oxidative damage caused by free radical attack. Lactic acid bacteria (Lactic acid bacteria) can directly play an antioxidant role in the intestinal tract to become a promising antioxidant. The rat liver homogenate lipid peroxidation induced by Fe2 / VITC was used as a model. The effect of 29 strains of lactic acid bacteria on inhibiting lipid peroxidation was analyzed. The results showed that the antioxidant activity of lactic acid bacteria was strain dependent, and the ability of removing ferrous ions from lactic acid bacteria was determined. Activities of intracellular superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were used to analyze the antioxidant mechanism of lactic acid bacteria. The correlation coefficients between the anti-lipid peroxidation of lactic acid bacteria and the three factors were 0.4070.559U 0.455P0.01g, respectively, but different lactic acid bacteria could mainly achieve antioxidation by different mechanisms. In this paper, we further established an in vitro model to simulate the colonic environment. In order to study the effect of antioxidant lactic acid bacteria on the content of hydroxyl free radical in colon and the composition of bacteria, L. paracasei Fn032L. Rhamnosus GG GG GG + LGG + L. sp Fn001 (the anti-lipid peroxidation ability were 95.31C 89.93% 29.41%) could decrease the content of .OH in different degree, and the effect of Lactic acid bacteria on the content of hydroxyl radical and bacterial composition in colon was studied. The proliferation of Escherichia coli and Enterococcus was inhibited, and Fn032GG significantly inhibited the proliferation of Escherichia coli and Enterococcus. The mice were fed with high iron diet (iron content 0.07%) and fed with lactic acid bacteria Fn032Fn001109CFU / day. The effects of different antioxidant lactic acid bacteria on the oxidative damage of colon chyme and intestinal mucosa induced by high iron were studied. The results showed that Fn032 GGG FN001 could decrease the content of ferrous ion and the content of malondialdehyde (MDA) in colon. The activity of SOD and GSH-Px in colon of mice was increased, the excessive proliferation of Escherichia coli and enterococcus was inhibited, the barrier function of intestinal mucosa was protected, and the level of liver endotoxin was decreased. Finally, DSS induced mouse enteritis model was established, and treated with LGG Fn037 L. acidophilus Fn037 and L. plantarum Fn003 (in vitro anti-lipid peroxidation ability were 89.93% and 82.41%, respectively). The effects of lactic acid bacteria (Lactic acid bacteria) on the oxidative damage of colon mucosa induced by inflammation were studied. The results showed that LGGfn037 could inhibit the oxidative damage of mucosa induced by enteritis, and significantly reduce the activity of MPO and the levels of Ros and MDA. To increase the total resistance of colon mucosa and the content of antioxidant enzymes P0.05, to maintain the normal intestinal flora, to protect the intestinal mucosa, and to significantly reduce the level of liver endotoxin (P0.05) Fn003 was not significant. Antioxidative lactic acid bacteria have the ability to produce SODH-Px or remove Fe2. These lactic acid bacteria can improve the redox status of colonic chyme and mucous membrane in mice. Antioxidation may be one of the mechanisms by which some lactic acid bacteria (Lactic acid bacteria) play a prebiotic role, and lactic acid bacteria (Lactic acid bacteria) with antioxidant effects have potential applications in food and medical fields.
【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2009
【分类号】：R371

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