铁皮石斛多糖对高脂饮食小鼠肠黏膜结构及菌群的影响

为考察铁皮石斛多糖对高脂饮食小鼠肠黏膜屏障的影响,采用水提醇沉法提取铁皮石斛多糖,联合高脂饲料给予小鼠8周后观察肠黏膜结构及肠黏膜菌群的变化。结果显示高脂饮食显著破坏了肠黏膜结构,表现为肠黏膜萎缩,上皮细胞脱落并伴有炎性渗出,Corynebacterium_1及Staphylococcus等与感染及炎症相关的菌属大量增殖。铁皮石斛多糖对肠黏膜结构有较好的保护作用,并可减少Corynebacterium_1的丰度,同时提高肠黏膜共生菌Candidatus_Arthromitus的丰度,促进了Muribaculaceae、Bacteroides、Lachnospiraceae_NK4A136_group等碳水化合物代谢、短链脂肪酸产生相关菌的增殖。研究表明铁皮石斛多糖对肠黏膜屏障的保护作用或与其维持肠黏膜结构完整,调节肠黏膜菌群组成及促进碳水化合物代谢,生成短链脂肪酸有关。     

高脂饮食中添加短链菊粉对小鼠肠道菌群的影响

目的:探究高脂饮食中添加短链菊粉对小鼠肠道菌群的影响。方法:选择8周龄雄性小鼠,5只喂食高脂饲料,5只喂食10%菊粉复合型高脂饲料,喂食8周后收集小鼠粪便,检测小鼠粪便中三种主要的短链脂肪酸。同时,提取小鼠粪便中的细菌基因组,对菌群基因组16S rRNA基因V4高变区进行测序,对数据进行PCoA分析、Alpha多样性分析、LEfSe分析和16S功能预测。结果:菊粉添加后,小鼠粪便中含有的细菌DNA量增多,短链脂肪酸增加。菊粉组和对照组PCoA图可以看到明显聚类。菊粉组物种多样性低于对照组。菊粉组小鼠粪便中S24_7菌科丰度上升;Lachnospiraceae(毛螺菌科),Ruminococcaceae(瘤胃菌科)和Deferribacteraceae(脱铁杆菌科)丰度下降。16S基因功能预测发现22个第二层级的KEGG通路发生变化。结论:高脂饮食情况下短链菊粉的添加会改变小鼠肠道菌群,继而影响肠道菌群的功能。     

基于肠道菌群和短链脂肪酸代谢探讨不同饮食条件下高脂血症大鼠发病机制

目的 本研究拟对比两种不同高脂饮食方式诱导的高脂血症大鼠肠道菌群变化与短链脂肪酸代谢特征,以宿主-肠道菌群-代谢角度探讨高脂血症可能的微观机制。方法 SPF级SD大鼠分为：正常饮食组(CG组):饲喂大鼠维持饲料;高脂饮食组(HFD1组):每天足量饲喂高脂饲料;限饲高脂饮食组(HFD2组):每天限量饲喂高脂饲料80 g,不限量饲喂维持饲料。8周后检测血清总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)和高密度脂蛋白胆固醇(HDL-C)水平;苏木精-伊红(HE)染色观察大鼠肝组织和肾周脂肪病理学变化;取结肠内容物进行16S rDNA高通量测序,观察肠道菌群结构与功能的变化,并检测结肠内容物中短链脂肪酸的含量。结果 与CG组相比,HFD1组和HFD2组大鼠摄食量下降,体重升高;血清中TC、TG、LDL-C均显著升高;肝组织发生明显脂肪变性,肾周脂肪出现炎性病变;高脂干预后大鼠肠道菌群相对丰度显著变化,其中乳杆菌属相对丰度明显降低,菌群结构和功能变化明显,总短链脂肪酸、乙酸、丁酸、异丁酸下降显著。结论 两种高脂饮食方式均能引起大鼠高脂血症,且发病机制基本一致,均与脂质代谢以...     

铁皮石斛对脾虚便秘小鼠肠道菌群多样性的影响

目的 探讨铁皮石斛对脾虚便秘小鼠肠道菌群的影响,为铁皮石斛对脾虚便秘的疗效机制及临床组方提供依据。方法 选取12只SPF级昆明小鼠随机分为正常组、模型组、铁皮石斛组和枳术汤组,每组3只。造模阶段正常组灌胃无菌水,模型组和治疗组采用番泻叶水煎液灌胃7 d后,限制饮食饮水8 d,建立脾虚便秘模型。造模成功后,正常组和模型组灌胃无菌水,治疗组分别以铁皮石斛和枳术汤水煎液干预5 d。治疗结束后,收集各组小鼠盲肠内容物样本进行16S rDNA高通量测序。结果 脾虚便秘小鼠排便量减少,粪便细小,干燥,质硬,呈黄色。铁皮石斛和枳术汤分别治疗后,小鼠排便量增加,粪便软硬适中,呈黑褐色。测序分析发现,正常组与铁皮石斛组的共有OTU数最多,与枳术汤组的共有OTU数最少。α-多样性指数与PCA结果表明,铁皮石斛组菌属结构较其余两组更接近正常组小鼠。物种相对丰度及组成结果表明,铁皮石斛增加了脾虚便秘小鼠双歧杆菌属相对丰度,抑制了乳杆菌属、拟杆菌属相对丰度,但对菌群丰度的调节作用不及枳术汤;LEfSe分析与随机森林分析鉴定出布劳特菌属和活泼瘤胃球菌是铁皮石斛组与其他组别的差异菌群。结论 铁皮石斛能恢复脾虚便秘小...     

广叶绣球菌多糖对免疫低下小鼠肠道免疫功能的调节作用

通过研究广叶绣球菌多糖对免疫低下小鼠肠道菌群、细胞因子表达量及短链脂肪酸的影响,探究广叶绣球菌多糖的免疫作用机制。腹腔注射环磷酰胺构建免疫低下小鼠模型,将小鼠分为6组：正常对照组、模型组、广叶绣球菌多糖低、中、高剂量组以及阳性对照组,连续饲养30d后处死取样,HE染色观察小肠组织结构,酶联免疫吸附法测定小肠白细胞介素-6（IL-6）、IL-10、肿瘤坏死因子-α（TNF-α）、干扰素-γ（IFN-γ）的表达水平,高通量测序技术分析小鼠肠道菌群的变化,气-质联用（GC-MS）技术分析盲肠内容物短链脂肪酸（SCFAs）的含量。结果表明,广叶绣球菌多糖高剂量组可显著改善绒毛肿胀和变短现象,提高绒毛长度/隐窝深度的比值（V/C值）和小肠IL-6、IL-10、TNF-α、IFN-γ细胞因子含量（P<0.05或P<0.01）,提高拟杆菌属Bacteroides、拟普雷沃菌属Alloprevotella、丁酸弧菌属Butyrivibrio、Intestinimonas、链球菌属Streptococcus的相对丰度（P<0.05或P<0.01）;各剂量组均可提高盲肠内6种主要短链脂肪酸含量,差异达显著或极显著水平（P<0.05或P<0.01）。试验组与阳性对照组趋势一致。广叶绣球菌多糖可通过改善免疫低下小鼠的肠道粘膜形态,提高小肠细胞因子水平,调节肠道菌群结构,增加SCFAs产生菌的相对丰度,提高短链脂肪酸含量,调节免疫低下小鼠的肠道免疫功能。     

高脂饮食诱导肠道微生物代谢产物短链脂肪酸改变进而影响食物过敏的发生

通过回顾过敏性疾病以及高脂饮食、肥胖等的大量研究报告,探究高脂饮食以及高脂饮食带来的肥胖是否会对食物过敏的发生产生影响以及可能的机制。研究发现,高脂饮食可能会增加食物过敏发生率,降低食物过敏阈值,增加食物过敏的风险,并且高脂饮食对肠道微生物的影响是其中的一个原因。高脂饮食改变肠道微生物结构,导致短链脂肪酸产生差异,而短链脂肪酸通过G蛋白偶联受体、组蛋白乙酰化等途径引起Treg细胞分化、IgA产生以及致耐受性的DC细胞产生,影响肠道屏障的健康,因此,高脂饮食对肠道微生物结构的改变带来的短链脂肪酸的产生差异影响了肠道屏障的健康,进而导致食物过敏的阈值降低,易感性增加。     

哺乳动物肠道微生物与碳水化合物的互作及其影响

肠道微生物具有调节宿主营养、免疫以及能量代谢等生理功能。饮食是影响哺乳动物的肠道微生物的一个重要因素。碳水化合物是哺乳动物食物能量的主要来源,因此研究肠道微生物与碳水化合物的代谢之间的关系及其影响具有重要意义。基于近年相关研究,本文从碳水化合物对肠道微生物组成的影响、肠道微生物对碳水化合物的代谢机制以及碳水化合物发酵产物短链脂肪酸对宿主的影响3个方面进行了综述。研究表明,肠道微生物可用于发酵的碳水化合物类型主要是抗性淀粉和非淀粉多糖;不同类型的碳水化合物会导致肠道菌群发生适应性变化;复杂多糖发酵产生的短链脂肪酸在调节宿主能量平衡和免疫应答方面发挥了重要作用。总结近年来相关研究,可加深对肠道菌群对宿主碳水化合物代谢贡献的理解,为哺乳动物机体健康状况的营养调控策略提供参考。     

铁皮石斛和百令胶囊对老年SD大鼠肠道菌群的影响

目的探讨铁皮石斛和百令胶囊对自然衰老SD大鼠肠道菌群组成和多样性的影响。方法选取自然衰老SD雄性大鼠30只随机分为5组,分别为铁皮石斛高(400 mg/kg)、中(200 mg/kg)、低(100 mg/kg)剂量组及百令胶囊组(40 mg/kg)、空白对照组,每组6只,对各组大鼠连续灌胃8周。在灌胃结束后,取各组大鼠的新鲜粪便,通过16S rRNA测序技术分析粪便菌群,采用生物信息学方法对大鼠肠道菌群结构和多样性进行分析。结果与空白对照组相比,PCoA和韦恩图分析结果显示铁皮石斛和百令胶囊使大鼠肠道菌群结构发生显著变化;铁皮石斛高剂量组放线菌门(Actinobacteria)菌群数量增多,Patescibacteria和厚壁菌门(Firmicutes)菌群数量减少,并且铁皮石斛高剂量组增加了肠道菌群种类的丰富度,如新增疣微菌门(Verrucomicrobia);百令胶囊组肠道菌群组成差异不显著,在原菌群的基础上调整其组成比例,表现为厚壁菌门数量增多,变形菌门(Proteobacteria)数量减少。结论铁皮石斛和百令胶囊对自然衰老大鼠肠道菌群具有调节作用,不同剂量的铁皮石斛对肠道菌群有不同的调节作用。铁皮石斛高剂量组对肠道菌群的调节具有重要意义,可增加有益菌的丰度,降低有害菌的丰度。     

绿豆对高脂饮食大鼠肠道微生物及脂代谢调节的影响

本文研究并评估了绿豆对高脂饮食大鼠血脂代谢(TG、TC、LDL-C、HDL-C)、肝脏脂质分布、抗氧化酶活性(SOD、CAT、T-AOC)的影响。还研究了绿豆对高脂饮食大鼠肠道微生物菌群及短链脂肪酸(SCFAs)的调节作用。结果表明,与高脂饮食组相比,添加绿豆显著减轻大鼠了血清和肝脏的脂质积累,并提高了抗氧化酶的活性。大鼠盲肠中的SCFAs含量随绿豆剂量的增加而增加。大鼠盲肠内容物以厚壁菌和拟杆菌为主。绿豆摄入影响了大鼠肠道微生物群的丰度,拟杆菌和放线菌相对丰度等增加。这些结果表明,绿豆具有改善肠道微生物及调节脂代谢的作用,对机体有显著的保护作用。     

短链脂肪酸对肠道动力影响的研究进展

人体的肠道不仅仅是消化吸收场所,也是大量微生物生存的家园。肠道作为人体最大的“储菌库”,其多种生理功能离不开复杂多变的肠道菌群和菌群代谢物(如短链脂肪酸等)的参与。短链脂肪酸是肠道菌群发酵膳食纤维产生的一类重要的信号分子,研究发现短链脂肪酸除参与维持人体肠道黏膜免疫屏障、调节体液及电解质平衡以及为肠上皮细胞提供能量外,还与肠道动力调节有关。本文就短链脂肪酸在肠道动力调节中的作用进行综述,旨在深入理解短链脂肪酸与肠道的互作关系,维持肠道的机械屏障,从而为探索肠道相关动力疾病的治疗提供新思路。     

Targeting the gut microbiota with resveratrol: a demonstration of novel evidence for the management of hepatic steatosis

Resveratrol is a natural polyphenol that has been reported to reduce the risk of obesity and nonalcoholic fatty liver disease (NAFLD). Recent evidence has demonstrated that the gut microbiota plays an important role in the protection against NAFLD and other metabolic diseases. The present study aimed to investigate the relationship between the gut microbiota and the beneficial effects of resveratrol on the amelioration of NAFLD in mice. We observed marked decreases in body weight and liver steatosis and improved insulin resistance in high-fat diet (HFD)-fed mice treated with resveratrol. Furthermore, we found that resveratrol treatment alleviated NAFLD in HFD-fed mice by improving the intestinal microenvironment, including gut barrier function and gut microbiota composition. On the one hand, resveratrol improved gut intestinal barrier integrity through the repair of intestinal mucosal morphology and increased the expression of physical barrier- and physiochemical barrier-related factors in HFD-fed mice. On the other hand, in HFD-fed mice, resveratrol supplementation modulated the gut bacterial composition. The resveratrol-induced gut microbiota was characterized by a decreased abundance of harmful bacteria, including Desulfovibrio, Lachnospiraceae_NK4A316_group and Alistipes, as well as an increased abundance of short-chain fatty acid (SCFA)-producing bacteria, such as Allobaculum, Bacteroides and Blautia. Moreover, transplantation of the HFDR-microbiota into HFD-fed mice sufficiently decreased body weight, liver steatosis and low-grade inflammation and improved hepatic lipid metabolism. Collectively, resveratrol would provide a potentially dietary intervention strategy against NAFLD through modulating the intestinal microenvironment.     

高脂食物对动脉硬化合并类风湿关节炎 小鼠肠道菌群的影响

目的分析高脂食物对动脉硬化合并类风湿关节炎小鼠肠道微生物的影响,了解动脉硬化合并类风湿关节炎小鼠肠道微生物的变化。方法 8周龄ApoE~(-/-)小鼠饲喂高脂食物和普通食物至17周龄来诱发动脉硬化症状,再通过给17周龄ApoE~(-/-)小鼠腹腔注射抗6-磷酸葡萄糖异构酶(glucose-6-phosphate isomerase,GPI)抗体呈阳性的K/BxN血清,从而诱导其产生类风湿关节炎症状。通过Illumina HiSeq平台对各组小鼠粪便进行16S rDNA V4区测序,分析动脉硬化合并类风湿关节炎小鼠肠道微生物的变化。结果 ApoE~(-/-)小鼠饲喂高脂食物后,其血清低密度脂蛋白胆固醇(LDL-C)浓度和血清总胆固醇(TC)浓度均显著升高,主动脉内膜斑块面积比喂普通食物的ApoE~(-/-)小鼠显著增加,表明ApoE~(-/-)小鼠饲喂高脂食物后引起更显著的动脉硬化症状。再通过腹腔注射抗GPI抗体呈阳性的K/BxN血清,各组ApoE~(-/-)小鼠均出现关节肿胀,饲喂高脂食物的ApoE~(-/-)小鼠其踝关节宽度和临床评分(clinical score)低于饲喂普通食物组小鼠。OTU数、Shannon指数和Simpson指数显示高脂食物和K/BxN血清处理组ApoE~(-/-)小鼠肠道菌群多样性降低,Firmicutes/Bacteroidetes值升高,t-test分析显示在属水平上,Prevotellaceae_UCG-001显著降低,Ruminiclostridium_6显著升高。t-test分析和Firmicutes/Bacteroidetes比值显示ApoE~(-/-)小鼠肠道菌群结构紊乱。结论高脂食物使ApoE~(-/-)小鼠的肠道菌群组成和结构发生改变,导致ApoE~(-/-)小鼠的动脉硬化症状加重,类风湿关节炎症状减轻。提示肠道微生物组成和结构的改变,可能与动脉硬化合并类风湿关节炎发病机制相关。     

A high-fat diet and high-fat and high-cholesterol diet may affect glucose and lipid metabolism differentially through gut microbiota in mice

This study was conducted to investigate the effects of a high-fat diet (HFD) and high-fat and high-cholesterol diet (HFHCD) on glucose and lipid metabolism and on the intestinal microbiota of the host animal. A total of 30 four-week-old female C57BL/6 mice were randomly divided into three groups (n=10) and fed with a normal diet (ND), HFD, or HFHCD for 12 weeks, respectively. The HFD significantly increased body weight and visceral adipose accumulation and partly lowered oral glucose tolerance compared with the ND and HFHCD. The HFHCD increased liver weight, liver fat infiltration, liver triglycerides, and liver total cholesterol compared with the ND and HFD. Moreover, it increased serum high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and total cholesterol compared with the ND and HFD and upregulated alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase significantly. The HFHCD also significantly decreased the α-diversity of the fecal bacteria of the mice, to a greater extent than the HFD. The composition of fecal bacteria among the three groups was apparently different. Compared with the HFHCD-fed mice, the HFD-fed mice had more Oscillospira, Odoribacter, Bacteroides, and [Prevotella], but less [Ruminococcus] and Akkermansia. Cecal short-chain fatty acids were significantly decreased after the mice were fed the HFD or HFHCD for 12 weeks. Our findings indicate that an HFD and HFHCD can alter the glucose and lipid metabolism of the host animal differentially; modifications of intestinal microbiota and their metabolites may be an important underlying mechanism.     

Effect of non-digestible gluco-oligosaccharides on glucose sensitivity in high fat diet fed mice

Non digestible dietary carbohydrates have been reported to modify lipaemia and post-prandial glycaemia and insulinaemia. The aim of this study was to investigate the effect of a non-digestible gluco-oligosaccharides (GOS) diet on glucose, insulin, triglycerides and free fatty acid blood levels and glucose sensitivity in high fat diet fed mice (a high fat diet composed of 45% fat, 35% carbohydrate and 20% protein). Female C57B16/J mice were divided into two groups fed a high fat diet (HF) for 20 weeks supplemented or not with 1.5 g/kg/day of GOS (HF-GOS). The GOS supplementation did not change body weight nor fat pad mass, nor any of the blood parameters measured (glucose, insulin, leptin, triglycerides, and free fatty acids). However, mice which received the GOS supplemented diet showed an increased glucose utilization after a 1 g/kg load of glucose compared with the mice fed the high fat diet alone. Our results suggest a role for non-digestible GOS in the regulation of carbohydrate metabolism.     

Short-Chain Fructo-Oligosaccharides Modulate Intestinal Microbiota and Metabolic Parameters of Humanized Gnotobiotic Diet Induced Obesity Mice

Prebiotic fibres like short-chain fructo-oligosaccharides (scFOS) are known to selectively modulate the composition of the intestinal microbiota and especially to stimulate Bifidobacteria. In parallel, the involvement of intestinal microbiota in host metabolic regulation has been recently highlighted. The objective of the study was to evaluate the effect of scFOS on the composition of the faecal microbiota and on metabolic parameters in an animal model of diet-induced obesity harbouring a human-type microbiota. Forty eight axenic C57BL/6J mice were inoculated with a sample of faecal human microbiota and randomly assigned to one of 3 diets for 7 weeks: a control diet, a high fat diet (HF, 60% of energy derived from fat)) or an isocaloric HF diet containing 10% of scFOS (HF-scFOS). Mice fed with the two HF gained at least 21% more weight than mice from the control group. Addition of scFOS partially abolished the deposition of fat mass but significantly increased the weight of the caecum. The analysis of the taxonomic composition of the faecal microbiota by FISH technique revealed that the addition of scFOS induced a significant increase of faecal Bifidobacteria and the Clostridium coccoides group whereas it decreased the Clostridium leptum group. In addition to modifying the composition of the faecal microbiota, scFOS most prominently affected the faecal metabolome (e.g. bile acids derivatives, hydroxyl monoenoic fatty acids) as well as urine, plasma hydrophilic and plasma lipid metabolomes. The increase in C. coccoides and the decrease in C. leptum, were highly correlated to these metabolic changes, including insulinaemia, as well as to the weight of the caecum (empty and full) but not the increase in Bifidobacteria. In conclusion scFOS induce profound metabolic changes by modulating the composition and the activity of the intestinal microbiota, that may partly explain their effect on the reduction of insulinaemia.     

益生菌干预对肥胖孕鼠子代菌群及脂代谢的影响

目的分析高脂高糖饮食诱导肥胖母亲对子代菌群及脂代谢影响。方法C57BL/6J雌性小鼠30只随机分为正常对照组、肥胖组、益生菌干预组,每组10只。分别给予标准饲料、高脂高糖饲料以及高脂高糖饲料同时给予益生菌,连续喂养6周,制成肥胖母鼠模型。6周后雌、雄鼠合笼,受孕,孕期继续上述饮食。产后母乳喂养,3周后处死。留取雌性子鼠第21天粪便样本进行PCR-DGGE分析,同时酶反应比色法分析子鼠血脂情况。结果与正常对照组子代相比,肥胖母鼠子代菌群结构出现异常,益生菌干预组子代肠道菌群失调状况明显改善;肥胖母鼠子代血清总胆固醇、低密度脂蛋白含量升高,益生菌干预组子代血脂异常情况明显改善。结论高脂高糖饮食诱导肥胖母亲子代存在肠道菌群紊乱及脂代谢异常,益生菌干预母亲有利于改善子代菌群紊乱及脂代谢异常。     

肠道菌群多糖利用及代谢

宿主与肠道共生菌之间存在一种互利共生的关系。肠道共生菌可以代谢宿主自身不能消化的多糖。进入肠道内的多糖是影响肠道共生菌生理状态和组成的重要因素,这些多糖主要来自饮食和宿主的粘膜分泌物。人类饮食中含有几十种不同的膳食多糖,其中大多数不能被人类基因组中编码的酶降解,并进入大肠,供肠道共生菌利用。肠道共生菌将这些不易消化的多糖转化为短链脂肪酸,作为大肠细胞和其他肠道上皮细胞的营养物质。除此之外,短链脂肪酸对人体健康有着重要的影响。不同的肠道共生菌对进入肠道内的多糖具有不同的偏好性,表明摄入膳食多糖是一种可以直接影响肠道内共生菌物种平衡的策略。因此,研究肠道菌群的多糖代谢机制具有重要的意义。本文从肠道共生菌的组成、利用进入肠道内多糖的机制,以及产生的代谢产物可能对人体健康存在的潜在影响等方面进行了综述,并介绍了代表性的肠道共生菌如拟杆菌和双歧杆菌利用多糖的途径及特征。     

Beneficial effects of eicosapentaenoic acid on the metabolic profile of obese female mice entails upregulation of HEPEs and increased abundance of enteric Akkermansia muciniphila

Eicosapentaenoic acid (EPA) ethyl esters are of interest given their clinical approval for lowering circulating triglycerides and cardiometabolic disease risk. EPA ethyl esters prevent metabolic complications driven by a high fat diet in male mice; however, their impact on female mice is less studied. Herein, we first investigated how EPA influences the metabolic profile of female C57BL/6J mice consuming a high fat diet. EPA lowered murine fat mass accumulation, potentially through increased biosynthesis of 8-hydroxyeicosapentaenoic acid (HEPE), as revealed by mass spectrometry and cell culture studies. EPA also reversed the effects of a high fat diet on circulating levels of insulin, glucose, and select inflammatory/metabolic markers. Next, we studied if the improved metabolic profile of obese mice consuming EPA was associated with a reduction in the abundance of key gut Gram-negative bacteria that contribute toward impaired glucose metabolism. Using fecal 16S-ribosomal RNA gene sequencing, we found EPA restructured the gut microbiota in a time-dependent manner but did not lower the levels of key Gram-negative bacteria. Interestingly, EPA robustly increased the abundance of the Gram-negative Akkermansia muciniphila, which controls glucose homeostasis. Finally, predictive functional profiling of microbial communities revealed EPA-mediated reversal of high fat diet-associated changes in a wide range of genes related to pathways such as Th-17 cell differentiation and PI3K-Akt signaling. Collectively, these results show that EPA ethyl esters prevent some of the deleterious effects of a high fat diet in female mice, which may be mediated mechanistically through 8-HEPE and the upregulation of intestinal Akkermansia muciniphila.