Zhongguo quanke yixue (Mar 2022)
Analysis of Gut Flora in a Mouse Model of Esophageal Squamous Cell Carcinoma in Situ
Abstract
BackgroundWith the application and development of high-throughput sequencing-based approaches for gut flora analysis, increasing studies have confirmed that gut flora is closely related to the development of various cancers. The relationship of gut floras with esophageal squamous cell carcinoma (ESCC) , a common cancer threatening the health of Chinese people, has attracted extensive attention.ObjectiveTo analyze the diversity of gut floras between a rat model of ESCC in situ and normal mice, to identify the carcinoma-specific bacterial genus in ESCC.MethodsFrom August 2020 to May 2021, 20 female SPF C57BL/6 mice were randomly and equally divided into control group and model group. Rice in control group were routinely fed and given ordinary drinking water for 32 weeks, and those in model group were routinely fed and received water containing 0.1 mg/ml cancer inducer 4-nitroquinoline-1-oxide for 16 weeks, and then only fed with ordinary drinking water for another 16 weeks. Stool samples of both groups were collected, and DNA in faeces was extracted and amplified by PCR, followed by high-throughput sequencing. The obtained sequencing data were divided into operational taxonomic units (OTU) based on the similarity between sequences. The α-diversity, β-diversity and species abundance were further analyzed according to species annotation.ResultsNo death occurred in the experiment, and the modeling of ESCC was successfully established in model group. Compared with control group, the proportion of Bacteroidota and Firmicutes increased, while the proportion of Verrucomicrobiota and Proteobacteria decreased in model group. Analysis showed that the α-diversity measured by Shannon Diversity Index in model group was lower than that of control group (P<0.05) . As for β-diversity analysis, PCoA diagram showed that the gut floras of control and model groups clustered in different quadrants, suggesting a significant discrepancy between the groups (t=22.444, P=0.004) . At the phylum level, the abundances of unidentified bacteria, Cyanobacteria, Elusimicrobia and Campilobacterota were higher in model group than those in control group (P<0.05) . At the genus level, the abundances of Prevotellaceae_UCG-003, Bacteroides and Lachnospiraceae_NK4A136_group, Ruminococcus, Prevotellaceae_UCG-001, Prevotella, Colidextribacter, Lachnospiraceae_UCG-006 were higher while those of Romboutsia and Turicibacter were lower in model group than those in control group (P<0.05) . LEfSe analysis showed that, at the genus level, the abundances of Prevotellaceae_UCG-003, Escherichia-Shigella, Bacteroides, Lachnospiraceae_NK4A136_group were increased significantly in model group (P<0.05) , but the abundance of Romboutsia was increased significantly in control group DZ (P<0.05) .ConclusionBy comparing the composition of gut flora, we identified the rat model of ESCC may have less diversity of species and specially differentiated bacteria, and Prevotellaceae_UCG-003, Bacteroides, Lachnospiraceae_NK4A136_group, and Romboutsia could be used as biomarkers for ESCC.
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