oral and intestinal microbiome variations and correlations in type 2 diabetes mellitus mice

Objective To investigate the composition and changes of the microbiota in the oral cavity and intestinal tract of mice under diabetic conditions, as well as the correlation between them. Methods Ten Six-week-old SPF-grade male db/db mice and ten db/m mice were selected, the fasting blood glucose (FBG) and oral glucose tolerance test (OGTT) of the two groups of mice were measured to verify the reliability of the diabetic model. Oral microbiota and fecal samples of the mice were collected, and 16S rDNA sequencing analysis was performed. Results Compared with db/m, the FBG and AUC of OGTT in the db/db group were significantly increased, and the morphology of pancreatic islet cells in the db/db group was significantly changed. The alpha diversity and beta results of the oral and intestinal microbiota of the two groups of mice indicated significant changes in the richness of the microbiota, and the community results also showed significant changes. Compared with the db/m group, the dysbiosis index of the oral and intestinal microbiota in the db/db group was significantly increased. The difference analysis between the microbiota groups and LEfSe analysis indicated that there were extensive differences in the oral and intestinal microbiota between the two groups of mice at the phylum and genus levels. The Spearman correlation analysis showed that g_Helicobacter and g_Gemella were significantly positively correlated in the oral and intestinal tracts, while g_norank_f_Lachnospiraceae in the oral and intestinal tracts showed significant negative correlations with each other. The g_Candidatus_Arthromitus and g_Helicobacter were significantly positively correlated in the oral and intestinal tracts, the g_Helicobacter and g_Gemella, g_Thomasclavelia and g_Faecalibaculum showed significant negative correlations in the intestinal and oral tracts. Conclusion The structure and richness of the intestinal microbiota in diabetic mice have significantly changed compared to normal control mice, and there is a significant correlation between the oral and intestinal tracts.