植物乳杆菌对小鼠铜暴露毒性缓解作用的研究

发布时间：2018-07-07 13:58

本文选题：植物乳杆菌 + 生物吸附　；参考：《江南大学》2014年硕士论文

【摘要】：环境污染致使大量的铜进入食物链中，并不断富集，严重威胁食品安全及人体健康。过量的铜会引发机体氧化应激反应和损伤，导致肝脏病变、脑部受损，出现肝肿大、神经衰弱、智力下降等症状。有研究表明，乳酸菌能够有效吸附铜离子，且乳酸菌具有抗氧化、消除人体自由基等免疫调节作用，此外使用成本低、属于食品安全级（GRAS）微生物等特点都是其优势所在。因此，探究膳食摄入益生乳酸菌是否能够缓解重金属铜毒性是一个非常具有研究意义的课题。本论文以乳酸菌作为研究对象，以对铜离子的吸附能力及耐受能力作为指标进行筛选，获得了一株对铜具有较强吸附能力及耐受能力的植物乳杆菌，，并对其进行了动物实验的功效验证及实际应用价值的开发。针对菌株对铜的吸附和耐受特性，选取16株乳酸菌进行体外筛选，得到一株能够高效吸附铜离子并且生长不受高浓度铜抑制的理想菌株植物乳杆菌CCFM8246，其最大吸附量达到19.7mg/g，在含铜离子浓度为50mg/L，150mg/L、500mg/L的MRS培养基中能够正常生长。在植物乳杆菌CCFM8246的体内实验功能评价中，通过灌胃小鼠铜溶液（浓度分别为100mg/kg，150mg/kg）成功建立小鼠铜暴露损伤模型，每日灌喂植物乳杆菌CCFM8246（2.0×1010CFU/mL，0.2mL）加以干预和治疗。每周收集粪便并记录体重等生理指标，通过水迷宫实验研究铜暴露对小鼠智力受损情况的影响及植物乳杆菌CCFM8246对相关损伤的缓解作用。处死小鼠后收集血液、肝脏、肾脏、脑等进行生理生化分析，比较组织和粪便中的铜含量、血清及组织匀浆的氧化应激相关指标。结果表明，与铜暴露模型组相比，植物乳杆菌CCFM8246灌胃组小鼠粪便中的铜含量显著升高，最高可达到6倍以上，说明植物乳杆菌CCFM8246能够有效降低小鼠肠道对铜的吸收。与之对应，植物乳杆菌CCFM8246灌胃组小鼠组织中铜含量明显降低，在最显著实验组中铜含量减少量可达到75.9%，进一步验证了其排铜作用。同时，植物乳杆菌CCFM8246对铜暴露毒性的两大重要器官肝脏和脑部也起到了一定的保护作用。植物乳杆菌CCFM8246灌胃组小鼠肝脏匀浆中谷胱甘肽过氧化物酶（GSH-PX）、超氧化物歧化酶（SOD）活性升高，而丙二醛（MDA）含量显著降低，表明植物乳杆菌CCFM8246能有效缓解铜暴露对肝脏造成的氧化损伤。血清中谷丙转氨酶（ALT）、谷草转氨酶（AST）活性降低，再次验证了植物乳杆菌CCFM8246对肝脏损伤的缓解作用。水迷宫实验也证实植物乳杆菌CCFM8246能够有效缓解铜暴露导致的小鼠智力损伤，提高学习记忆能力。本研究结果显示，植物乳杆菌CCFM8246确实具有缓解小鼠铜毒性作用，可以作为一个新的饮食治疗方法治疗铜诱导损伤。植物乳杆菌CCFM8246在豆乳制品中的应用研究表明，该菌株在豆乳中生长情况良好，感官品质较佳。由此可见，植物乳杆菌CCFM8246具有发酵豆乳制品的潜力与优势，可用于相关产品的研究开发和商业化生产。
[Abstract]:Environmental pollution causes a large amount of copper into the food chain and enriching, which seriously threatens food safety and human health. Excessive copper can cause oxidative stress reaction and damage to the body, causing liver disease, brain damage, hepatomegaly, neurasthenia, mental decline and so on. Studies have shown that lactic acid bacteria can effectively adsorb copper ions, and Lactic acid bacteria have the antioxidation, eliminate the immune regulation of human free radicals and so on. In addition, it has the advantages of low cost, which belong to the food safety grade (GRAS) microorganism. Therefore, it is a very important task to explore whether the dietary intake of probiotic lactic acid bacteria can alleviate the toxicity of heavy metal copper. As an object of study, a plant lactobacillus with strong adsorption capacity and tolerance to copper was obtained by screening the adsorption capacity and tolerance capacity of copper ions, and the efficacy of animal experiments and the development of practical application value were also carried out.
In view of the adsorption and tolerance characteristics of the strain to copper, 16 strains of lactic acid bacteria were selected in vitro to obtain an ideal strain of Lactobacillus plantarum CCFM8246, which could efficiently adsorb copper ions and grow without high concentration of copper. The maximum adsorption capacity reached 19.7mg/g. In the MRS medium containing the concentration of copper ion concentration of 50mg/L, 150mg/L and 500mg/L Normal growth.
In the evaluation of the experimental function of Lactobacillus plantarum CCFM8246 in vivo, the mice copper exposure damage model was established by gavage of mice copper solution (100mg/kg, 150mg/kg). The mice were fed with Lactobacillus plantarum CCFM8246 (2 x 1010CFU/mL, 0.2mL) daily to intervene and treat them. The effect of copper exposure on mental impairment in mice and the alleviating effect of Lactobacillus plantarum CCFM8246 on related damage in mice was studied. The blood, liver, kidney and brain were collected and the copper content in tissue and feces were compared, and the related indexes of oxidative stress in serum and tissue homogenate were compared. Compared with the exposed model group, the copper content in the feces of the mice treated with Lactobacillus plantarum CCFM8246 was significantly higher than that of 6 times, indicating that Lactobacillus plantarum CCFM8246 could effectively reduce the absorption of copper in the intestinal tract of mice. The copper content in the mouse group of Lactobacillus plantarum CCFM8246 was significantly reduced and the most significant experimental group was in the most significant experimental group. The reduction of copper content could reach 75.9%, which further verified the effect of copper excretion. At the same time, Lactobacillus plantarum CCFM8246 also played a protective role in the liver and brain of two important organs of copper exposure toxicity. The glutathione peroxidase (GSH-PX) and superoxide dismutase (SOD) in the liver homogenate of mice treated with Lactobacillus plantarum The activity increased and the content of malondialdehyde (MDA) decreased significantly, indicating that Lactobacillus plantarum CCFM8246 could effectively alleviate the oxidative damage caused by copper exposure to the liver. The activity of cereal alanine aminotransferase (ALT) and glutarine transaminase (AST) in serum was reduced. The remission of Lactobacillus plantarum CCFM8246 to liver injury was verified. The water maze test also confirmed the plant milk. Bacilli CCFM8246 can effectively alleviate the mental impairment in mice caused by copper exposure and improve the learning and memory ability. The results of this study showed that Lactobacillus plantarum CCFM8246 did alleviate copper toxicity in mice and could be used as a new dietary therapy to treat copper induced injury.
The application of Lactobacillus plantarum CCFM8246 in soybean milk products showed that the strain grew well in soybean milk and had better sensory quality. Thus, Lactobacillus plantarum CCFM8246 had the potential and advantage of fermented soybean milk products, and could be used in the research and development of related products and commercial production.
【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R965

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