Akkermansia muciniphila亚型改善高脂饮食诱导的小鼠代谢紊乱及神经退行性变

发布时间：2018-06-13 06:43

本文选题：AKK亚型 + 精神疾病　；参考：《南方医科大学》2017年硕士论文

【摘要】：肥胖及糖尿病严重威胁着人类健康,它们也能显著增加神经精神类疾病的发病率,如抑郁症、痴呆、中风及记忆力衰退等。全身慢性系统性炎症是肥胖及糖尿病患者的共同特征,这样的慢性炎症也出现在中枢神经系统内,它是连接肥胖、糖尿病和神经精神疾病的重要纽带。Akkermansia muciniphila(简称为AKK)2004年被首次分离培养。研究发现AKK与肥胖及2型糖尿病密切相关,在2型糖尿病患者中,AKK的数量显著显著下降。此外,动物研究发现,给予AKK灌胃能显著改善由高脂饮食诱导的代谢紊乱,包括像脂肪堆积,内毒素血症,肥胖病及胰岛素抵抗等.最新的研究发现,同一种的细菌不同菌株对体内免疫细胞的作用不一定是相同或相似的,也存在一些刚好“相左”的作用。即虽然它们结构相似,却并不完全起到协同作用,也存在相互制衡。本团队从临床粪便样本中分离出一株AKK,并经过测序分析确认其是与模式菌株不同的亚型(简称为AKK亚型)。1研究目的:1.1确认该AKK亚型的减缓体重增加和改善血糖控制的功能及探索其作用机制。1.2探索该AKK亚型能否预防肥胖相关精神疾病的出现及其作用的机制。2方法2.1 40只8周龄SPF级雌性C57BL/6小鼠随机分为四组,分别为高脂饮食灌胃组,高脂饮食对照组,正常饮食灌胃组,正常饮食对照组。灌胃组每天每只小鼠按2×108CFU/0.2ml剂量给予AKK亚型灌胃,对照组给予相同体积的PBS灌胃。每周测量小鼠体重及饲料消耗量,实验持续10个月。2.2实验中期及结束时测定小鼠的空腹血糖,进行口服糖耐量实验2.3实验前及实验后测定粪便中AKK的定植量2.4实验结束时进行糖水偏爱实验和Y迷宫实验,分析小鼠的抑郁及空间记忆情况。2.5肠道菌群宏基因组学测序2.6血清中炎症及脑功能相关指标检测2.7体外测定AKK亚型及模式菌株产生短链脂肪酸2.8病理学观察2.9统计学分析3结果3.1 AKK亚型能显著减少高脂饮食及正常饮食小鼠的饲料消耗量,显著减轻高脂饮食小鼠的体重。3.2灌胃前各组小鼠AKK的定植量没有显著差异,灌胃后,灌胃组的定植量显著高于对照组。3.3 AKK亚型能降低高脂饮食小鼠的空腹血糖及提高糖耐受能力。3.4糖水偏爱:高脂饮食小鼠的糖水消耗率均显著低于正常饮食小鼠;AKK亚型灌胃不能改善小鼠抑郁情况;Y迷宫实验:AKK亚型灌胃显著改善高脂饮食小鼠的空间记忆力。3.5正常灌胃组IL-10浓度显著高于另外三组,高脂灌胃组的IL-10也略高于另外两组;高脂对照组色氨酸显著高于另外三组,另外三组的色氨酸浓度没有显著差异;高脂饮食小鼠的五羟色胺浓度均显著低于正常饮食小鼠。3.6饮食因素能显著改变肠道菌群结构,高脂饮食显著降低肠道菌群多样性,并导致双歧杆菌数量下降,拟杆菌及嗜胆菌属数量上升;AKK亚型能显著增加双歧杆菌属,降低嗜胆菌属,并与拟杆菌成负相关关系。3.7 AKK亚型能增加高脂饮食小鼠肠道中的杯状细胞的数量并能减轻肝脏脂肪变性。3.8 AKK亚型能产生比模式菌株更高浓度的乙酸、丙酸和异戊酸。4结论4.1 AKK亚型能显著减缓高脂饮食小鼠体重增加,并改善血糖控制4.2 AKK亚型能改善由于高脂饮食诱导的记忆力衰退4.3 AKK亚型可能通过提高肠道中双歧杆菌,降低嗜胆菌属及拟杆菌,产生短链脂肪酸及降低机体炎症水平对宿主发挥作用
[Abstract]:Obesity and diabetes are a serious threat to human health. They can also significantly increase the incidence of neuropsychiatric disorders, such as depression, dementia, stroke, and memory decline. Systemic chronic systemic inflammation is a common feature of obesity and diabetes. This chronic inflammation is also found in the central nervous system, which is linked to obesity and sugar. .Akkermansia muciniphila (AKK), an important link between urinary and neuropsychiatric disorders, was first isolated in 2004. The study found that AKK is closely related to obesity and type 2 diabetes. In type 2 diabetic patients, the number of AKK is significantly decreased. In addition, animal studies have found that giving AKK to the stomach can significantly improve the induction of high fat diet. Metabolic disorders, including fat accumulation, endotoxemia, obesity and insulin resistance. Recent studies have found that different strains of the same bacteria do not have the same or similar effects on immune cells in the body, and there are some just "left" effects. The team isolated a AKK from the clinical stool sample and sequenced it to confirm that it was a subtype (AKK subtype) that was different from the model strain (referred to as AKK subtype).1 research purposes: 1.1 confirm the AKK subtype's weight loss increase and improve the function of blood glucose control and explore its mechanism of action.1.2 to explore whether the AKK subtype is possible The mechanism of prevention of obesity related mental illness and its mechanism.2 method 2.140 8 weeks old SPF female C57BL/6 mice were randomly divided into four groups: high fat diet gavage group, high fat diet control group, normal diet gavage group, normal diet control group. Each mice in the gavage group were given the AKK subtype of AKK subtype every day at 2 x 108CFU/0.2ml doses per mouse. The control group was given the same volume of PBS gavage. The weight and feed consumption of mice were measured every week. The experiment lasted 10 months at the mid-term and the end of the.2.2 experiment. The experiment was carried out before and after the oral glucose tolerance test (2.3), and the fixed amount of AKK in the feces was measured at the end of the experiment of sugar water preference and the Y labyrinth experiment. Analysis of depression and spatial memory in mice.2.5 intestinal microflora sequencing 2.6 serum inflammation and brain function related indicators detection 2.7 in vitro determination of AKK subtype and pattern strain producing short chain fatty acid 2.8 pathological observation 2.9 statistical analysis 3 Results 3.1 AKK subtype can significantly reduce the diet of high fat diet and normal diet mice feeding There was no significant difference in the amount of AKK in the mice before gavage of high fat diet (.3.2). After gavage, the colonization of the gavage group was significantly higher than that of the control group.3.3 AKK subtype, which could reduce the fasting blood glucose of the high fat diet mice and improve the sugar tolerance.3.4 sugar water preference: the sugar water consumption rate of the high fat diet mice were all Significantly lower than normal diet mice, AKK subtype of gastric perfusion could not improve the depression of mice; Y labyrinth experiment: AKK subtype of gastric perfusion significantly improved the spatial memory of high fat diet mice, IL-10 concentration in the normal gavage group was significantly higher than the other three groups, and the IL-10 in the high fat gavage group was slightly higher than the other two groups, and the high fat control group was significantly higher than that of the other group. In the three group, there was no significant difference in the concentration of tryptophan in the other three groups; the concentration of five HT in the high fat diet mice was significantly lower than the.3.6 diet in the normal diet mice. The high fat diet significantly reduced the diversity of the intestinal flora, and the number of bifidobacteria, and the increase in the number of Bacillus and eosinophilia; AKK The subtype can significantly increase the genus Bifidobacterium and lower the genus pheophilia, and the.3.7 AKK subtype can increase the number of goblet cells in the intestinal tract of the high fat diet mice and reduce the liver fatty degeneration.3.8 AKK subtype to produce a higher concentration of acetic acid than the model strain. The 4.1 AKK subtype of propionic acid and isovalerate.4 can be found to be significant. The increase in weight of the high fat diet mice and the improvement of the 4.2 AKK subtype of blood glucose control can improve the memory decline induced by the high fat diet 4.3 AKK subtypes by raising the Bifidobacterium in the intestinal tract, reducing the phinophilia and bacteriobacteria, producing short chain fatty acids and reducing the level of inflammatory disease to the host.
【学位授予单位】：南方医科大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R741;R58

【参考文献】