小鼠粪便及肠道各部位内容物细菌群落结构差异分析

摘要

目的：分析小鼠粪便及肠道各部位内容物细菌群落结构差异，探讨粪便取样研究肠道微生物与疾病关系的科学性和客观性，为相关实验设计提供参考。方法利用末端限制性片段长度多态性（ T－RFLP）、变性梯度凝胶电泳（ DGGE）和荧光定量PCR（ qPCR）技术对BALB／c小鼠肠道不同部位（十二指肠、空肠、回肠、盲肠、结肠和直肠）内容物及粪便中细菌群落组成和丰度进行比较，分析细菌群落在小鼠粪便及肠道各部位的分布差异。结果粪便与直肠、结肠中优势片段均为244、255 bp和449 bp，而小肠内容物（十二指肠、空肠及回肠）的优势片段则为60、73、261、268 bp和272 bp，且小肠各部位之间细菌群落结构差异较大；十二指肠和空肠内容物中的细菌丰度较低，分别为6．9 log （copies）／g和8．3 log （copies）／g，而粪便中细菌丰度高达11．8 log （copies）／g，约2倍于十二指肠细菌丰度，显著高于十二指肠和空肠（P ＜0．05），与大肠各部位及回肠内容物细菌丰度相当，差异不显著（P＞0．05）。结论大肠各部位内容物和粪便的细菌群落结构相似，个体差异较小肠小，适合通过粪便取样进行大肠部位特别是结直肠的肠道微生态与某些疾病的相关分析。%Objective To explore the objectivity and scientificity of fecal sampling , and to provide reference for investigating the relationship between intestinal microbes and diseases . Methods Terminal restriction fragment length polymorphism, degeneration gradient gel electrophoresis and real time fluorescent quantitative PCR techniques were applied to differentially analyze the bacterial community composition and abundance of intestinal contents and feces taken from dif -ferent sites of BALB/c mouse intestine .Results The predominant T-RFLP fragments ( T-RFs) in feces in the rectum and colon were 244 bp, 255 bp and 449 bp, however , those in feces of the small intestine including duodenum , jejunum and il-eum were 60 bp, 73 bp, 261 bp, 268 bp and 272 bp, and with a larger variation of the bacterial community composition in various parts of the small intestine .The bacterial abundance in the contents of duodenum and jejunum were 6.9 log ( cop-ies)/g and 8.3 log (copies)/g, fewer than in the other parts of the intestine , while the bacterial abundance in the feces was as high as 11.8 log (copies)/g, being about 2 times higher than that in the duodenum and jejunum (P<0.05), and similar to that in the ileum and colon content (P>0.05).Conclusions The inter-mouse variations of bacterial communi-ty composition in the large intestine contents are small .The bacterial composition and abundance are similar suggest that studies on the relationship between large intestine especially colorectal microbiota and diseases may be conducted via fecal sampling.