Oral malodorous compound inhibits osteoblast proliferation.
BACKGROUND
Oral malodorous compounds including hydrogen sulfide (H2S) are causative agents of periodontitis because the toxicities are similar to that of cyanate. Previous studies demonstrated that volatile sulfur compounds (VSCs) were highly toxic to periodontal tissues, causing a large reduction in the amount of collagen in human gingival fibroblasts and extracellular matrix as well as, for example, apoptosis, immunologic responses, and matrix metalloproteinase production. The objective of this study was to determine the effect of H2S on the proliferation of osteoblasts and a signaling transduction pathway through the mitogen-activated protein kinase (MAPK).


METHODS
Normal human osteoblasts (NHOst) and murine osteoblasts (cell line MC3T3-E1) were incubated with H2S. Cell proliferation was assessed by measuring [3H]thymidine incorporation. The effects of H2S on the signal transduction pathways, the MAPK cascade, that control cell proliferation were evaluated in NHOst by determining extracellular signal-regulated kinase (ERK)1/2 and p38 phosphorylation with a Western blot analysis.


RESULTS
After incubating NHOst with H2S for 24 hours, [3H]thymidine incorporation into the DNA significantly decreased dose-dependently with H(2)S. At a concentration of 100 ng/ml H2S, [3H]thymidine incorporation decreased 79% compared to the control. Similar results were obtained from MC3T3-E1. The phosphorylation of ERK1/2 and p38 was increased by H2S at 10 minutes after starting the treatment and then decreased time dependently. The activation of ERK1/2 and p38 induced by H2S was inhibited by the specific inhibitor of MAPK/ERK kinase ([MEK]; U0126) or p38 (SB203580).


CONCLUSIONS
H2S inhibited the proliferation of human osteoblastic cells through the MAPK pathway.
Imai
Toshio
T
Department of Oral Health, School of Life Dentistry at Tokyo, Nippon Dental University, Tokyo, Japan. imai-109@tky.ndu.ac.jp
Ii
Hisataka
H
Yaegaki
Ken
K
Murata
Takatoshi
T
Sato
Tsutomu
T
Kamoda
Takeshi
T
D016475:3T3 Cells; D000469:Alkaline Phosphatase / Q000032:analysis / Q000187:drug effects; D000818:Animals; D002070:Butadienes / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004247:DNA / Q000032:analysis / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006209:Halitosis / Q000378:metabolism; D006801:Humans; D006862:Hydrogen Sulfide / Q000008:administration & dosage / Q000494:pharmacology*; D007093:Imidazoles / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000187:drug effects; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000187:drug effects; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000187:drug effects; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000187:drug effects; D009570:Nitriles / Q000494:pharmacology; D010006:Osteoblasts / Q000187:drug effects*; D010766:Phosphorylation; D011725:Pyridines / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases / Q000187:drug effects
D002070:Butadienes; D004791:Enzyme Inhibitors; D007093:Imidazoles; D009570:Nitriles; D011725:Pyridines; C113580:U 0126; D004247:DNA; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D000469:Alkaline Phosphatase; C093642:SB 203580; D006862:Hydrogen Sulfide