title: Brazilian propolis mitigates impaired glucose and lipid metabolism in experimental periodontitis in mice.
abstract: BACKGROUND
  Periodontitis has been implicated as a risk factor for metabolic disorders associated with insulin resistance. Recently, we have demonstrated that orally administered Porphyromonas gingivalis, a representative periodontopathic bacterium, induces endotoxemia via reduced gut barrier function coupled with changes in gut microbiota composition, resulting in systemic inflammation and insulin resistance. Propolis, a resinous substance collected by honeybees from leaf buds and cracks in the bark of various plants, can positively affect metabolic disorders in various experimental models. In this study, we thus aimed to clarify the effect of propolis on impaired glucose and lipid metabolism induced by P. gingivalis administration.
  
  
  METHODS
  Eight-week-old male C57BL/6 mice were orally administered P. gingivalis strain W83, propolis ethanol extract powder with P. gingivalis, or vehicle. We then analyzed the expression profile of glucose and lipid metabolism-related genes in the liver and adipose tissues. Serum endotoxin levels were also evaluated by a limulus amebocyte lysate test. In addition, we performed histological analysis of the liver and quantified alveolar bone loss by measuring the root surface area on the lower first molar.
  
  
  RESULTS
  Oral administration of P. gingivalis induced downregulation of genes that improve insulin sensitivity in adipose tissue (C1qtnf9, Irs1, and Sirt1), but upregulation of genes associated with lipid droplet formation and gluconeogenesis (Plin2, Acox, and G6pc). However, concomitant administration of propolis abrogated these adverse effects of P. gingivalis. Consistent with gene expression, histological analysis showed that administered propolis suppressed hepatic steatosis induced by P. gingivalis. Furthermore, propolis inhibited the elevation of serum endotoxin levels induced by P. gingivalis administration. Contrary to the systemic effects, propolis had no beneficial effect on alveolar bone loss.
  
  
  CONCLUSIONS
  These results suggest that administration of propolis may be effective in suppressing periodontopathic bacteria-induced metabolic changes that increase the risk of various systemic diseases.
authors: Research Unit for Oral-Systemic Connection, Laboratory of Periodontology and Immunology, Division of Oral Science for Health Promotion, Niigata University Graduate School of Medical and Dental Sciences, 5274 Gakkocho 2-ban-cho, Chuo-ku, Niigata, 951-8514, Japan.|Division of Periodontology, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors: Mayuka
authors: M
authors: Nakajima
authors: Division of Periodontology, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors: Kei
authors: K
authors: Arimatsu
authors: Division of Periodontology, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors: Takayoshi
authors: T
authors: Minagawa
authors: Research Unit for Oral-Systemic Connection, Laboratory of Periodontology and Immunology, Division of Oral Science for Health Promotion, Niigata University Graduate School of Medical and Dental Sciences, 5274 Gakkocho 2-ban-cho, Chuo-ku, Niigata, 951-8514, Japan.|Division of Periodontology, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors: Yumi
authors: Y
authors: Matsuda
authors: Research Unit for Oral-Systemic Connection, Laboratory of Periodontology and Immunology, Division of Oral Science for Health Promotion, Niigata University Graduate School of Medical and Dental Sciences, 5274 Gakkocho 2-ban-cho, Chuo-ku, Niigata, 951-8514, Japan.|Division of Periodontology, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors: Keisuke
authors: K
authors: Sato
authors: Research Unit for Oral-Systemic Connection, Laboratory of Periodontology and Immunology, Division of Oral Science for Health Promotion, Niigata University Graduate School of Medical and Dental Sciences, 5274 Gakkocho 2-ban-cho, Chuo-ku, Niigata, 951-8514, Japan.|Division of Periodontology, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors: Naoki
authors: N
authors: Takahashi
authors: Division of Dental Educational Research Development, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors: Takako
authors: T
authors: Nakajima
authors: Research Unit for Oral-Systemic Connection, Laboratory of Periodontology and Immunology, Division of Oral Science for Health Promotion, Niigata University Graduate School of Medical and Dental Sciences, 5274 Gakkocho 2-ban-cho, Chuo-ku, Niigata, 951-8514, Japan. kaz@dent.niigata-u.ac.jp.
authors: Kazuhisa
authors: http://orcid.org/0000-0002-1893-4202
authors: K
authors: Yamazaki
mesh_terms: D016301:Alveolar Bone Loss / Q000378:metabolism; D000818:Animals; D001786:Blood Glucose / Q000187:drug effects*; D001835:Body Weight / Q000187:drug effects; D001862:Bone Resorption / Q000378:metabolism; D001938:Brazil; D019446:Endotoxemia / Q000378:metabolism; D050356:Lipid Metabolism / Q000187:drug effects*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010518:Periodontitis / Q000378:metabolism* / Q000382:microbiology; D016966:Porphyromonas gingivalis / Q000472:pathogenicity; D011429:Propolis / Q000737:chemistry / Q000494:pharmacology*; D020011:Protective Agents / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D001786:Blood Glucose; D020011:Protective Agents; D011429:Propolis
keywords: Adipose tissue; Endotoxemia; Liver; Periodontitis; Porphyromonas gingivalis; Propolis