Calcium hydroxide reduces lipopolysaccharide-stimulated osteoclast formation.
OBJECTIVE
The purpose of this study was to determine the direct effects of lipopolysaccharide (LPS) on osteoclastogenesis and to assess the ability of calcium hydroxide-Ca(OH)(2)-to inhibit the osteoclast formation stimulated by LPS.


METHODS
RAW 264.7 cells were cultured with 50 ng/mL recombinant receptor activator of NF-kappaB ligand (RANKL) for 72 hours. RANKL was then removed, and the cells were treated with 0, 1, 10, or 100 ng/mL of LPS, Ca(OH)(2)-treated LPS, or 50 ng/mL of RANKL as a positive control for an additional 48 hours. Cells were fixed and stained with fluorescein isothiocyanate-conjugated phalloidin to detect actin ring formation, and histochemistry was performed to detect multinucleated cells expressing tartrate-resistant acid phosphatase activity.


RESULTS
LPS induced osteoclast-like cell (OCL) formation in a dose-dependent manner when osteoclast precursor RAW 264.7 cells were pretreated for 72 hours with RANKL. Ca(OH)(2) significantly inhibited the ability of LPS to stimulate OCL formation.


CONCLUSIONS
This study shows that LPS directly stimulates OCL formation. The detoxification of LPS by treatment with Ca(OH)(2) significantly reduced its ability to trigger the differentiation of OCLs.
Jiang
Jin
J
College of Dentistry, Department of Endodontics, University of Florida, Gainsville 32610-0436, USA. jjiang@dental.ufl.edu
Zuo
Jian
J
Chen
Shih-Hua
SH
Holliday
L Shannon
LS
D000135:Acid Phosphatase / Q000378:metabolism; D000199:Actins / Q000096:biosynthesis; D000818:Animals; D002126:Calcium Hydroxide / Q000494:pharmacology*; D002352:Carrier Proteins / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D007527:Isoenzymes / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008562:Membrane Glycoproteins / Q000494:pharmacology; D051379:Mice; D010010:Osteoclasts / Q000187:drug effects*; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D011994:Recombinant Proteins / Q000494:pharmacology; D012388:Root Canal Irrigants / Q000494:pharmacology*; D000071681:Tartrate-Resistant Acid Phosphatase
D000199:Actins; D002352:Carrier Proteins; D007527:Isoenzymes; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D011994:Recombinant Proteins; D012388:Root Canal Irrigants; C505687:Tnfrsf11a protein, mouse; C505689:Tnfsf11 protein, mouse; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase; D002126:Calcium Hydroxide