Correlation Between Gut Microbiota And Radiation Enteritis Induced By Pelvic Tumor Radiotherapy

Objective:By analyzing the differences of intestinal flora between patients with radiation enteritis(RE)and patients with non-radiation enteritis(no RE)before radiotherapy in patients with pelvic tumor.We aim to evaluate the correlation between intestinal flora and RE,and aim to provide therapeutic value of microecological preparation for RE.Methods:1.Fecal samples of patients with pelvic tumor who received pelvic radiation treatment in the 900 th Hospital of the Joint Logistics hospital from February 2018 to June 2019 were collected within 1 week before and after radiotherapy,the patients’ clinical data and the symptoms related to RE were collected.2.The fecal samples were sent to genomic company for 16 S r RNA sequencing and analysis(V3-V4 region).The abundance and diversity of different groups of gut microbiota were analyzed by DNA extraction,PCR amplification,fluorescence quantification,library construction and sequencing.3.SPSS 23.0 software was used for statistical analysis in this study.All hypothesis tests were performed using the bilateral test,and the confidence interval was 95%.Results:A total of 46 patients were enrolled,and 68 fecal samples were collected(46before and 22 after radiotherapy).The incidence of RE was 56.52%.Dysbiosis was observed among patients with RE,which was characterized by significantly reduced α-diversity but increased β-diversity.The abundance of bacteria in the RE group was lower compared with the no RE group.At the level of phylum,firmicutes and bacteroidetes decreased in the RE group,while the abundance of proteobacteria was increased.In the RE group,the abundance of bacteriaceae,s24-7 bacteriaceae,Bacteroides-plebeius,Bacteroides-sp-4-1-36 and other bacteria were increased significantly,while the abundance of 36 types of bacteria,such as red bugs,lactobacaceae,propionibacterium etc.were decreased significantly compared with no RE group.The biodiversity and abundance of intestinal flora after radiotherapy were all reduced compared with that before radiotherapy,and the probiotics such as prevotella and proteobacteria were significantly reduced in the RE group after radiotherapy.Conclusion:Our results suggest that pelvic radiation therapy may lead to a decrease in the diversity and richness of intestinal flora in patients.There were differences in the bacterial flora between the RE group and the no RE group before radiotherapy,and the decrease of short-chain fatty acid fungi and the increase of proteobacteria in the intestinal tract of patients before radiotherapy might be related to the occurrence of radiation enteritis.