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目的:通过16S rDNA测序技术探究脓毒症大鼠早期肠道微生态变化。方法:将60只雄性SD大鼠按随机数字表法分为盲肠结扎穿孔术（CLP）组和假手术组（Sham组），每组30只。CLP组采用CLP法制备脓毒症大鼠模型；Sham组只开腹但不进行盲肠结扎穿孔。术后24 h每组取8只大鼠肠道粪便及腹主动脉血，其余大鼠用于观察7 d存活情况。采用酶联免疫吸附试验（ELISA）检测血清肿瘤坏死因子-α（TNF-α）水平；对粪便样本进行16S rDNA测序，利用序列对比和聚类后获得的操作分类单元（OTU）信息进行多样性分析（α多样性和β多样性）、主坐标分析及线性判别分析效应量分析（LEfSe），观察脓毒症大鼠早期肠道微生态的变化并挖掘标志性菌群。结果:制模后24 h，CLP组大鼠出现呼吸急促、毛发散乱等表现，且血清TNF-α水平较Sham组显著升高（ng/L：43.95±9.05比11.08±3.27，n P0.05〕；β多样性分析显示，无论是否根据OTU加权，组间差异均大于组内差异（丰度加权矩阵：n R＝0.23，n P＝0.04；丰度不加权矩阵：n R＝0.32，n P＝0.01）。门水平差异菌群分析显示，与Sham组相比，CLP组变形菌门和TM7菌门丰度显著升高〔18.100%（15.271%，26.665%）比6.974%（2.854%，9.764%），0.125%（0.027%，0.159%）%比0.018%（0.008%，0.021%），均n P<0.05〕；在属水平上，CLP组螺杆菌属、钌杆菌属、颗粒链菌属、梭菌属ⅩⅧ等机会致病菌的丰度较Sham组显著升高〔5.090%（1.812%，6.598%）比0.083%（0.034%，0.198%），0.244%（0.116%，0.330%）比0.016%（0.008%，0.029%），0.006%（0.003%，0.010%）比0.001%（0%，0.003%），0.094%（0.035%，0.430%）比0.007%（0.003%，0.030%），均n P<0.05〕，而拟普雷沃菌属、罗姆布茨菌属等益生菌的丰度较Sham组显著降低〔7.345%（3.662%，11.546%）比22.504%（14.403%，26.928%），0.113%（0.047%，0.196%）比1.229%（0.809%，2.290%），均n P<0.01〕。LEfSe分析结果显示，厚壁菌门所属益生菌在Sham组显著富集，罗姆布茨菌是富集最显著的菌种；而螺杆菌属、颗粒链球菌属和梭菌属ⅩⅧ等机会致病菌在CLP组显著富集，螺杆菌_NGSU_2015为富集最显著的菌种。n 结论:脓毒症早期大鼠肠道微生态结构显著改变，主要表现为拟普雷沃菌属等益生菌丰度显著降低，螺杆菌属等机会致病菌丰度显著升高。“,”Objective:To investigate the changes of intestinal microecology in the early stage of sepsis rat model by 16S rDNA sequencing.Methods:Sixty male Sprague-Dawley (SD) rats were randomly divided into cecal ligation and puncture (CLP) group and sham operation group (Sham group), with 30 rats in each group. In the CLP group, sepsis rat model was reproduced by CLP method; the rats in the Sham group only underwent laparotomy without CLP. At 24 hours after the operation, the intestinal feces and serum samples of 8 rats in each group were collected. The survival rate of the rest rats was observed until the 7th day. The level of serum tumor necrosis factor-α (TNF-α) was detected by enzyme-linked immunosorbent assay (ELISA). Intestinal feces were sequenced by 16S rDNA sequencing technology. The operational taxonomic unit (OTU) data obtained after sequence comparison and clustering was used for α diversity and β diversity analysis, principal coordinate analysis and linear discriminant analysis effect size analysis (LEfSe) to observe the changes of intestinal microecology in early sepsis rats and excavate the marker flora.Results:At 24 hours after the reproduction of the model, the rats in the CLP group showed shortness of breath, scattered hair and other manifestations, and the level of serum TNF-α increased significantly as compared with that in the Sham group (ng/L: 43.95±9.05 vs. 11.08±3.27,n P 0.05). However, the β diversity analysis showed that the difference between groups was greater than that within groups whether weighted according to OTU or not (abundance weighted matrix: n R = 0.23, n P = 0.04; abundance unweighted matrix: n R = 0.32, n P = 0.01). At the phylum level, the abundance of n Proteobacteria and n Candidatus_sacchari in the CLP group increased significantly as compared with the Sham group [18.100% (15.271%, 26.665%) vs. 6.974% (2.854%, 9.764%), 0.125% (0.027%, 0.159%)% vs. 0.018% (0.008%, 0.021%), both n P < 0.05]. At the genus level, the abundance of opportunistic pathogen including n Helicobacter, n Ruthenium, n Streptococcus, n Clostridium ⅩⅧ in the CLP group was significantly higher than that in the Sham group [5.090% (1.812%, 6.598%) vs. 0.083% (0.034%, 0.198%), 0.244% (0.116%, 0.330%) vs. 0.016% (0.008%, 0.029%), 0.006% (0.003%, 0.010%) vs. 0.001% (0%, 0.003%), 0.094% (0.035%, 0.430%) vs. 0.007% (0.003%, 0.030%), all n P < 0.05], and the abundance of probiotics such as n Alloprevotella and n Romboustia was significantly lower than that in the Sham group [7.345% (3.662%, 11.546%) vs. 22.504% (14.403%, 26.928%), 0.113% (0.047%, 0.196%) vs. 1.229% (0.809%, 2.29%), both n P < 0.01]. LEfSe analysis showed that the probiotics belonging to n Firmicutes were significantly enriched in the Sham group, and n Romboustia was the most significantly enriched species. Opportunistic pathogens such as n Helicobacter, n Streptococcus and n Clostridium ⅩⅧ were significantly enriched in the CLP group, n Helicobacter_NGSU_ 2015 was the most significantly enriched species.n Conclusion:In the early stage of sepsis, the intestinal microbiota structure of rats is significantly changed, which mainly shows that the abundance of n Alloprevotella and other probiotics is significantly reduced, while that of n Helicobacter and other opportunistic pathogens is significantly increased.n