法医学杂志

法医学杂志 ›› 2018, Vol. 34 ›› Issue (5): 482-486.DOI: 10.12116/j.issn.1004-5619.2018.05.005

所属专题： 死亡时间推断

• 专题 • 上一篇    下一篇

大鼠死后肠道菌群演替规律

李  欢1，刘睿娜2，张思若1，袁  璐1，徐纪茹1   

  1. 1. 西安交通大学医学部基础医学院，陕西 西安 710061； 2. 西安交通大学医学部法医学院，陕西 西安 710061
  • 发布日期:2018-10-25 出版日期:2018-10-28
  • 通讯作者: 徐纪茹，女，教授，博士研究生导师，主要从事临床医学、生物学、感染性疾病及传染病研究；E-mail：xujiru@mail.xjtu.edu.cn
  • 作者简介:李欢（1989—），女，博士，主要从事肠道菌群与死亡时间的关系研究；E-mail：1154736255@qq.com
  • 基金资助:
    国家自然科学基金重点资助项目（81730056）

Succession Law of Intestinal Flora after Death in SD Rats

LI Huan1, LIU Rui-na2, ZHANG Si-ruo1, YUAN Lu1, XU Ji-ru1   

  1. 1. School of Basic Medicine, Xi’an Jiaotong University Health Science Center, Xi’an 710061, China; 2. College of Forensic Science, Xi’an Jiaotong University Health Science Center, Xi’an 710061, China
  • Online:2018-10-25 Published:2018-10-28

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摘要： 目的 初步探索尸体肠道菌群的时序性变化用于死亡时间推断。 方法 利用棉签擦拭颈椎脱臼处死大鼠肠道取样，通过提取肠道菌群DNA，选取16S rRNA V3区通用引物进行PCR，PCR产物进行变性梯度凝胶电泳，对得到的图谱进行组间菌群多样性与相似性分析，并对从变性梯度凝胶电泳切下的条带进行纯化、PCR、测序后获得各组厚壁菌门的主要菌群所占百分比。 结果 处死后大鼠第1~30天的菌群多样性呈现减少趋势（P<0.05），组内相似性呈现下降趋势（P<0.05），第1天指纹图谱条带数、组内相似性系数（similarity coefficient，Cs）高于其他组（P<0.05），第5天与第25、30天组内Cs比较差异有统计学意义（P<0.05）。在属水平，处死后第1、5天肠道菌群以肠球菌属（Enterococcus sp.）为主，第10、15、20天以苏云金芽孢杆菌（Bacillus thuringienssis）为主，第25、30天以粪肠球菌（Enterococcus faecalis）为主。 结论 肠道菌群随大鼠处死后时间的延续，其组成、结构都出现了明显的变化，肠道菌群的演替与死亡时间相关。

关键词: 法医病理学, DNA指纹法, 变性梯度凝胶电泳, 大肠菌群, 死亡时间, 大鼠

Abstract: Objective To initially explore the sequential changes in the intestinal flora of corpse for the estimation of postmortem interval （PMI）. Methods Rats were sacrificed by cervical dislocation, and samples were taken from their intestines using cotton swab to extract the DNA of intestinal flora. The 16S rRNA V3 universal primers were selected for PCR, and the PCR products were used for denatured gradient gel electrophoresis. The diversity and similarity analysis of intestinal flora were analyzed between groups, and the bands were cut from denaturing gradient gel electrophoresis. After purification, PCR and sequencing, the percentage of major bacteria in each group was obtained. Results The flora diversity showed a reduced tendency from 1st to 30th day after death （P<0.05）, while the intra-group similarity showed a downward trend （P<0.05）. The number of bands and intra-group similarity coefficient （Cs） on the first day was higher than that of other groups （P<0.05）. The intra-group Cs of the 25th and 30th day had a significant difference compared with the 5th day （P<0.05）. At the genus level, the intestinal flora was mainly composed of Enterococcus sp. on the 1th and 5th day after death, Bacillus thuringienssis was the dominant species on the 10th, 15th and 20th day, and Enterococcus faecalis became the dominant species on the 25th and 30th day. Conclusion The composition and structure of intestinal flora change significantly in rats with the time after death, which indicates that the succession of intestinal flora is related to the postmortem interval.

Key words: forensic pathology, DNA fingerprinting, denaturing gradient gel electrophoresis, coliform, postmortem interval, rats