To observe the temporal shifts of the intestinal microbial community structure and diversity in rats for 30 days after death. Rectal swabs were collected from rats before death (BD) and on day 1, 5, 10, 15, 20, 25, and 30 after death (AD). Bacteria genomic DNA was extracted and V3 + V4 regions of 16S rRNA gene were amplified by PCR. The amplicons were sequenced at Illumina MiSeq sequencing platform. The bacterial diversity and richness showed similar results from day 1 to 5 and day 10 to 25 all presenting downtrend, while from day 5 to 10 showed slightly increased. The relative abundance of Firmicutes and Proteobacteria displayed inverse variation in day 1, 5, 10 and that was the former decreased, the latter increased. Bacteroidetes , Spirochaete and TM7 in day 15, 20, 25, 30 was significantly decline comparing with BD. Enterococcus and Proteus displayed reduced trend over day 1, 5, 10 and day 10, 15, 20, 25, respectively, while Sporosarcina showed obvious elevation during day 15, 20, 25. Accordingly, there was a certain correlation between intestinal flora succession and the time of death. The results suggested that intestinal flora may be potential indicator to aid estimation of post-mortem interval (PMI).

中文翻译：

---

SD大鼠死亡30天后肠道微生物变化的分子特征

观察大鼠死后30天肠道微生物群落结构和多样性的时间变化。在死亡前 (BD) 和死亡后第 1、5、10、15、20、25 和 30 天 (AD) 从大鼠中收集直肠拭子。提取细菌基因组DNA，PCR扩增16S rRNA基因的V3+V4区。扩增子在 Illumina MiSeq 测序平台上进行测序。细菌多样性和丰富度在第 1 天至第 5 天和第 10 天至第 25 天均呈下降趋势，而从第 5 天至第 10 天略有增加。Firmicutes 和 Proteobacteria 的相对丰度在第 1、5、10 天显示出相反的变化，即前者减少，后者增加。与BD相比，第15、20、25、30天拟杆菌、螺旋体和TM7显着下降。肠球菌和变形杆菌分别在第 1、5、10 天和第 10、15、20、25 天呈减少趋势，而孢子藻在第 15、20、25 天呈明显升高。因此，肠道菌群演替与死亡时间。结果表明，肠道菌群可能是帮助估计死后间隔 (PMI) 的潜在指标。