title: Combined effects of hydrogen sulfide and lipopolysaccharide on osteoclast differentiation in rats.
abstract: BACKGROUND
  Lipopolysaccharide (LPS) stimulates osteoclast differentiation through toll-like receptors (TLRs) 2 and 4, and hydrogen sulfide (H(2)S) induces osteoclast differentiation. If H(2)S activates TLRs, H(2)S may enhance the effects of LPS on osteoclast differentiation. The purpose of the present study is to examine the combined effects of sodium hydrogen sulfide (NaHS, an H(2)S donor drug) and LPS on osteoclast differentiation and TLR expression in rat periodontal tissue.
  
  
  METHODS
  Twenty-eight male Wistar rats (8 weeks old) were divided into four groups (n = 7 per group): a control (no treatment) group and three experimental groups (NaHS group, LPS group, and a combination [NaHS + LPS] group). At 1 day after topical application of NaHS and/or Porphyromonas gingivalis LPS into the gingival sulcus of first molars, the number of tartrate-resistant acid phosphate (TRAP)-positive osteoclasts in the periodontal tissue was counted. Expression of TLR2 and TLR4 mRNAs and proteins in the gingival was also assessed.
  
  
  RESULTS
  The number of TRAP-positive osteoclasts was significantly higher in the combination group than in any other group (P <0.01). The combination group had 11.0-fold higher TLR4 mRNA levels than the control group. TLR4 protein levels were also higher in the combination group than in the NaHS or LPS group. However, the TLR2 mRNA and protein levels were not significantly different in the combination group and the LPS group.
  
  
  CONCLUSIONS
  In rat periodontal tissue, NaHS and LPS had an additive effect on osteoclast differentiation through activation of the TLR4 pathway but not the TLR2 pathway.
authors.affiliation: Department of Preventive Dentistry, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Irie
authors.forename: Daisuke
authors.initials: D
authors.lastname: Ekuni
authors.forename: Takaaki
authors.initials: T
authors.lastname: Tomofuji
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Endo
authors.forename: Kenta
authors.initials: K
authors.lastname: Kasuyama
authors.forename: Ken
authors.initials: K
authors.lastname: Yaegaki
authors.forename: Manabu
authors.initials: M
authors.lastname: Morita
mesh_terms: D000135:Acid Phosphatase / Q000032:analysis; D000818:Animals; D015415:Biomarkers / Q000032:analysis; D015153:Blotting, Western; D002452:Cell Count; D002454:Cell Differentiation / Q000187:drug effects; D005881:Gingiva / Q000187:drug effects; D024243:HMGB1 Protein / Q000187:drug effects; D006862:Hydrogen Sulfide / Q000494:pharmacology*; D007527:Isoenzymes / Q000032:analysis; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D010010:Osteoclasts / Q000187:drug effects*; D010519:Periodontium / Q000166:cytology / Q000187:drug effects; D016966:Porphyromonas gingivalis; D053245:RANK Ligand / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D000071681:Tartrate-Resistant Acid Phosphatase; D051195:Toll-Like Receptor 2 / Q000187:drug effects; D051197:Toll-Like Receptor 4 / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000187:drug effects
chemical_list: D015415:Biomarkers; D024243:HMGB1 Protein; C104200:Hbp1 protein, rat; D007527:Isoenzymes; D008070:Lipopolysaccharides; D053245:RANK Ligand; C495343:Tlr2 protein, rat; C495347:Tlr4 protein, rat; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase; D006862:Hydrogen Sulfide