实验性结肠炎小鼠肠道菌群指纹图谱分析

Analysis of finger-print of the intestinal flora in mice with experimental colitis

目的检测实验性结肠炎小鼠肠道菌群多样性的总体变化和可培养细菌菌群的变化,研究菌群变化与实验性结肠炎的关系。方法小鼠分为正常对照组和模型组,每组10只,模型组每天给予2.5%DSS自由饮用,建立急性溃疡性结肠炎模型。正常对照组自由饮用生理盐水,第7天处死小鼠,分离结肠,提取黏膜细菌组DNA,应用细菌16S rDNA的PCR-SSCP技术对小鼠肠道菌落进行初步鉴定,对其组成结构进行分析,留取部分远端结肠进行菌群定植数量分析。结果模型组和正常对照组的所有样品分别进行3次以上的PCR-SSCP指纹图谱分析,得到了稳定可重复的图谱。模型组小鼠同正常对照组相比,菌群多样性明显减少。肠球菌和肠杆菌数量增多,乳酸杆菌和双歧杆菌数量明显减少。两组比较主要是不可培养细菌的差异。结论实验性结肠炎小鼠肠道菌群菌属多样性减少,各肠道菌属间存在比例失调,肠道微生态失调可能参与了结肠炎的产生或加重过程。

Objective To investigate the bacterial species of the intestinal flora in mice with experimental colitis and study its relationship with experimental colitis. Methods The composition of the common cultured intestinal microflora in mueosal samples was investigated by classical bacterial culture. Single strand conformation polymorphism （SSCP） a- nalysis was used to determine microbial diversity in mueosal samples. Results Stable and repeatable intestinal flora fin- ger-prints were obtained by PCR-SSCP. Diversity of the normal controls was significantly higher compared with the model group. Considering not only number of bands but also their intensity, analysis of the most obviously different bands indi- cated that the main difference between the two groups was the uncultured bacteria. Baterial culture indicated that Staph- ylococcus aureus and the total count of aerobian were increased significantly in acute experimental colitis mice compared with controls. Conclusion Diversity of the microflora was reduced in experimental colitis. Disproportionality existed in intestinal bacteria, intestinal microflora imbalance may be invdved in the production process or exacerbation of colitis.