Oral Administration of P. gingivalis Induces Dysbiosis of Gut Microbiota and Impaired Barrier Function Leading to Dissemination of Enterobacteria to the Liver

PLoS One. 2015 Jul 28;10(7):e0134234. doi: 10.1371/journal.pone.0134234. eCollection 2015.


Although periodontitis has been implicated as a risk factor for various systemic diseases, the precise mechanisms by which periodontitis induces systemic disease remain to be elucidated. We have previously revealed that repeated oral administration of Porphyromonas gingivalis elicits endotoxemia via changes in the gut microbiota of the ileum, and thereby induces systemic inflammation and insulin resistance. However, it is not clear to what extent a single administration of P. gingivalis could affect gut microbiota composition, gut barrier function, and subsequent influx of gut microbiota into the liver. Therefore, in the present study, C57BL/6 mice were orally administered P. gingivalis (strain W83) once and compared to sham-inoculated mice. The phylogenetic structure and diversity of microbial communities in the gut and liver were analyzed by pyrosequencing the 16S ribosomal RNA genes. Serum endotoxin activity was determined by a Limulus amebocyte lysate test. Gene expression in the intestine and expression of 16S rRNA genes in the blood and liver were examined by quantitative polymerase chain reaction. Administration of P. gingivalis significantly altered gut microbiota, with an increased proportion of phylum Bacteroidetes, a decreased proportion of phylum Firmicutes, and increased serum endotoxin levels. In the intestinal tissues, gene expression of tjp-1 and occludin, which are involved in intestinal permeability, were downregulated. Higher amounts of bacterial DNA were detected in the liver of infected mice. Importantly, changes in gut microbiota preceded systemic inflammatory changes. These results further support the idea that disturbance of the gut microbiota composition by orally derived periodontopathic bacteria may be a causal mechanism linking periodontitis and systemic disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Animals
  • Bacteroidaceae Infections / complications*
  • Bacteroidaceae Infections / microbiology
  • Dysbiosis / etiology*
  • Dysbiosis / metabolism
  • Dysbiosis / pathology
  • Endotoxemia / etiology
  • Endotoxemia / metabolism
  • Endotoxemia / pathology
  • Enterobacteriaceae / physiology
  • Enterobacteriaceae Infections / etiology*
  • Enterobacteriaceae Infections / metabolism
  • Enterobacteriaceae Infections / pathology
  • Feces / microbiology
  • Gastrointestinal Microbiome*
  • Humans
  • Inflammation / etiology*
  • Inflammation / metabolism
  • Inflammation / pathology
  • Inflammation Mediators / metabolism
  • Liver / microbiology*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Porphyromonas gingivalis / physiology*
  • RNA, Ribosomal, 16S


  • Inflammation Mediators
  • RNA, Ribosomal, 16S

Grant support

This work was supported by the Japan Society for the Promotion of Science KAKENHI 23390476, 25670882, and 15H02578 (KY); The Japan Science and Technology Agency (HO); and Sunstar Inc. (KY). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.