Characteristics of Oral-Gut Microbiota in Model Rats with CUMS-Induced Depression

Abstract

Purpose

The diversity and composition of the oral and gut microbiota of depressed rats were analyzed to explore the microbiological etiology of major depressive disorder (MDD).

Methods

The depressed rat model was established by inducing chronic unpredictable mild stress (CUMS). After the establishment of the model, body weight measurements and behavioral tests were conducted. The diversity and composition of oral and gut microbiota were analyzed using 16SrRNA sequencing.

Results

There were significant differences in the alpha and beta diversity of the oral microbiota of rats in the CUMS and control groups. The top three most abundant genera in the oral microbiota were Rothia, Psychrobacter, and Streptococcus. Linear discriminant analysis effect size (LEfSe) analysis showed that the abundance of Rothia decreased and that of Psychrotrophs increased in the CUMS group, and the differences were statistically significant. The top three most abundant genera in the gut microbiota were Lactobacillus, Ruminococcus and Oscillospira. LEfSe analysis showed that the abundance of Ruminococcus decreased in the CUMS group, and the difference was statistically significant. Spearman correlation analysis was performed to analyze the differential microbiota and depression-like behavior, which showed that differential microbiota significantly correlated with body weight, total distance traveled, average speed, and number of rearing. Spearman correlation analysis of oral and gut differential microbiota demonstrated a strong positive correlation between Facklamia in the oral cavity and Enterococcus, Streptococcus in the intestine (r=0.64–0.73, P<0.01); along with a strong negative correlation between Desulfovibrio in the oral cavity and Enterococcus, Turicibacter in the intestine(r=−0.51-−0.72, P<0.05).

Conclusion

Significant differences were observed in the diversity and composition of oral and gut microbiota between the CUMS depression model and control groups. Modulating the oral and gut microbiota may have positive effects on MDD.

Keywords:

• major depressive disorder
• oral microbiota
• gut microbiota
• 16SrRNA sequencing

Ethics Statement

This study complies with the Chinese National Laboratory Animal-Guidelines for Ethical Review of Animal Welfare (GB/T35892-2018) and was approved by the Medical Ethics Committee of First Hospital of Shanxi Medical University. The approval number is DWYJ-2023-148.

Acknowledgments

We would like to express our appreciation and gratitude to all of the participants in this study. The authors also acknowledge Miss Yanyan Zhang in Department of Psychiatry, First Hospital of Shanxi Medical University who has contributed to the research program.

Disclosure

All authors declare that they have no conflicts of interest for this work.

Additional information

Funding

This study was financially supported by the National Natural Science Youth Fund Project (82201691), and the Science and Technology Innovation Project in Higher Education Institutions of Shanxi Province(2023L477).