ABSTRACT
Objective:To investigate the correlation between the changes of oral bacterial flora during head and neck radiotherapy and radiation-induced oral mucositis (ROM).Methods:The oral bacterial samples of patients with nasopharyngeal carcinoma and accompanying family members were obtained before and at the end of radiotherapy and subjected to high-throughput sequencing. C57BL/6 mice were used to establish the ROM models. On the 9 th day after radiotherapy, oral bacterial samples were collected in the radiotherapy group and the negative control group. On the 3 rd, 5 th, 7 th, and 9 th days post-radiotherapy, the tongue tissues were obtained from another batch of mice in the negative control and radiotherapy groups. Inflammatory factors were detected with PCR and HE staining was performed. Results:The oral bacterial diversity of patients after radiotherapy significantly differed from that of patients before radiotherapy and their accompanying family members before and after radiotherapy in Observed species, Chao1, Simpson index (all P<0.05). There was a significant difference in Shannon index between the severe and mild ROM patients ( P=0.036). LEfSe analysis showed that patients with severe ROM had higher levels of g_ Streptococcus and f_ Streptococcus, and lower levels of f_ Familyxl, g_ Gemini and o_ Bacillus. The Simpson index and PCoA results in the oral bacterial samples significantly differed between the negative control and radiotherapy groups (all P<0.05). Conclusions:Radiotherapy can disrupt the balance of bacterial flora. The dysregulated oral bacterial flora is closely associated with the aggravation of ROM.
ABSTRACT
Objective To analyze the diversity of salivary bacteria in patients with nonalcoholic fatty liv-er disease(NAFLD group)and healthy control group(HC group). Methods Saliva samples were collected from 24 patients with nonalcoholic fatty liver disease and 22 healthy control.Genomic DNA of the samples was extracted and extended to 16S rRNA V4-V5 hypervariable region after PCR with Illumina high-throughput sequencing tech-nology.All the data,including operational taxonomic units,diversity indexes and species annotation,etc.was ana-lyzed. Results 39118 optimized sequences in the saliva of each group were obtained,including nonalcoholic fatty liver group clustering OTUs about 308 ± 48 and healthy control group clustering OTUs about 305 ± 53.The diversi-ty analysis of NAFLD group and HC group showed that there was little difference in diversity of the whole salivary bacteria.The data of the species analysis of the saliva bacteria in two group indicate that the composition was simi-lar and the relative abundance was different in phylum and genus.In NAFLD group,the ratio of the abundance of firmicutes(20.42%)increased and the proportion of bacteroides(36.75%)decreased in phylum. Genus of the NAFLD group,the ratio of fusobacterium,porphyromonas and veillonella increased significantly,and the ratio of prevotella and[Prevotella]decreased.Conclusion In the NAFLD group,the abundance of firmicutes increased, and the abundance of the bacteria decreased.It was speculated that the imbalance of the salivary bacteria is associ-ated with nonalcoholic fatty liver disease.