肥胖小鼠肠内容物与肠道黏膜的菌群多样性分析

Diversity analysis of luminal and mucosa-associated microbial communities in obese mice

目的探讨肥胖小鼠肠内容物与肠道黏膜的菌群多样性差异。方法C57BL/10小鼠高脂喂养12周（10只），收集小鼠结肠内容物与结肠黏膜样本，提取肠道菌群DNA，Illumina平台二代测序。对测序结果进行物种注释、多样性和物种差异分析。结果肥胖小鼠结肠内容物及结肠黏膜的菌群丰富度和均匀度相同（ACE指数250比285，Chao指数257比291，Shannon指数3.84比3.97，Simpson指数0.05比0.06，P值均〉0.05），群落构成大部分相似；但在具体物种组成上有差异，在门水平，肠内容物较肠黏膜有更多的拟杆菌门（56.08%比27.25%，P=0.000），结肠黏膜则拥有更多的厚壁菌门（49.09%比34.27%，P=0.03）和变形菌门（18.48%比3.62%，P=0.001）。在属水平，产短链脂肪酸的乳杆菌属在肠内容物中丰度更高（LDA=3.89），革兰阴性的幽门螺杆菌、鞘脂单胞菌属、脱硫弧菌属在结肠黏膜中相对丰度更高（LDA分别为4.78、3.59、4.11）。结论肥胖小鼠结肠黏膜和肠内容物尽管多样性与群落总体构成相似，但门、属水平的菌群组成仍有不同。

ObjectiveGut microbiota have been reported to be able to regulate host metabolism and is closely associated to obesity. The purpose of this study was to explore the differences between the diversity of luminal and mucosa-associated microbial communities in obese mice. MethodsColonic luminal contents and colonic mucosa were separately collected from 10 obese mice fed with high-fat diet for 12 weeks. DNA of gut microbiota was extracted and micro flora populations were analyzed by Illumina sequencing. Species annotation, diversity analysis, and species difference analysis were conducted.ResultsThe microbial flora from colonic contents had similar richness, evenness and overall structure to those from colonic mucosa （ACE index 250 vs. 285, Chao index 257 vs. 291, Shannon index 3.84 vs. 3.97, Simpson index 0.05 vs. 0.06, all P〉0.05）. However, there were differences in the microbial composition on specific levels. At the phylum level, colonic contents had higher abundance of Bacteroidetes （56.08% vs. 27.25%, P=3.21×10-5）, while colonic mucosa had higher abundance of Firmicutes （49.09% vs. 34.27%, P=0.03） and proteobacteria （18.48% vs. 3.62%, P=0.000 9）. At the genus level, butyrate-producing bacteria-Lactobacillus was more abundant in colonic content （LDA score=3.89）, whereas gram-negative genus Helicobacter, Sphingomonas and Desulfovibrio were relatively abundant in colonic mucosa （LDA score=4.78, 3.59 and 4.11, respectively）. ConclusionThere were differences in microbial composition at the phylum and genus levels between microbial flora from colonic contents and colonic mucosa, although they had similar richness, evenness and overall structure.