摘要：目的：探究老年痴呆症的发生与粪便菌群结构的关系，为预防和治疗老年痴呆症奠定理论基础。方法：用粪便采样器采集正常小鼠和老年痴呆症小鼠便进行粪便标本预处理后，采用酚一氯仿方法提取样本菌群基因组DNA，并进行16S rRNA基因V3区片段PCR扩增，扩增产物用变性梯度凝胶电泳法(denaturing gradient gel electrophoresis，DGGE)检测分析．结果：采用该方法成功地扩增出16S rRNA基因V3区230bp的片段，经DGGE的方法，用bionumberics软件分析DGGE结果，可以比较出正常小鼠与老年痴呆症小鼠样本菌群结构在同种样本中相似度在60%-80%左右，在不同样本之间相似度仅为30%-40%左右．结论：基于16S rRNA基因V3区的PCR-DGGE技术能够应用于研究粪便微生物结构，结果表明：正常小鼠与老年痴呆症小鼠粪便样本中微生物菌群存在明显差异。

关键词：16S rRNA基因；聚合酶链式反应；变性梯度凝胶电泳

Abstract：Study on the relationship of the occurrence of Alzheimer's disease and the structure of fecal microflora,establish the theoretical basis for preventing and treating Alzheimer's disease．A sampler was used to collect the fecal samples from healthy mice and sick mice．Total bacteria genomic DNA was extracted from the fecal samples by the method of phenol-chloroform after pre-treatment．For 16S rRNA gene V3 region PCR amplification，and PCR products were detected and analyzed by denaturing gradient gel electrophoresis(DGGE)．It is found that the method can amplify 16S rRNA gene V3 specific regions of the 230bp fragment successfully．The detected results by the DGGE and bionumberics software method can compare different fecal bacteria structures between healthy mice and sick mice．The similar samples's similarity ranges from 60% to 80% approximately,the different samples's similarity only ranges from 30% to 40% approximately．It is concluded that the PCR—DGGE technology based on 16S rRNA gene V3 region can be applied in the study of fecal microbial diversity，the research demonstrate that the sampler was used to collect the fecal samples from healthy mice and sick mice have distinct differences．

Key words: 16S rRNA gene；PCR；DGGE