Abstract
The anabolic effects of prostaglandin E(2) on bone are effected through the activation of EP4, a G protein-coupled receptor. In the present study, we examined the effects of a prostanoid receptor-selective agonist (ONO-4819) in an experimental system of ectopic bone formation using recombinant human bone morphogenetic protein-2 (rhBMP-2). Collagen pellets containing rhBMP-2 were implanted onto the back muscles of mice and then treated with ONO-4819 administered every 8 h by subcutaneous injection. The ossicles elicited ectopically by rhBMP-2 in mice treated with 30 microg/kg ONO-4819 were significantly larger in size and had a higher bone mineral density and bone mineral content when compared to the controls. We also noted that the anabolic effect of ONO-4819 was seen only in the early phase of the rhBMP-2-induced bone-forming process. These experimental results indicate that the EP4 receptor agonist enhances the rhBMP-2-induced bone formation through a selective effect on early stage mesenchymal cells, which in turn may result in increased responsiveness of the host animals to rhBMP-2.
MeSH terms
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Absorbable Implants
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Absorptiometry, Photon / methods
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Alkaline Phosphatase / metabolism
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Animals
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Body Weight / drug effects
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Bone Density / drug effects
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Bone Morphogenetic Protein 2
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Bone Morphogenetic Proteins / genetics
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Bone Morphogenetic Proteins / pharmacology*
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Bone and Bones / diagnostic imaging
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Bone and Bones / metabolism*
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Bone and Bones / ultrastructure
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Collagen
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Dose-Response Relationship, Drug
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Drug Carriers
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Heptanoates / pharmacology*
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Humans
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Male
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Mice
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Mice, Inbred ICR
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Osteocalcin / blood
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Osteogenesis / drug effects*
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Receptors, Prostaglandin E / agonists*
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Receptors, Prostaglandin E, EP4 Subtype
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Recombinant Proteins / genetics
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Recombinant Proteins / pharmacology
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Transforming Growth Factor beta*
Substances
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BMP2 protein, human
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Bmp2 protein, mouse
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Bone Morphogenetic Protein 2
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Bone Morphogenetic Proteins
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Drug Carriers
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Heptanoates
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ONO4819
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PTGER4 protein, human
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Ptger4 protein, mouse
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Receptors, Prostaglandin E
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Receptors, Prostaglandin E, EP4 Subtype
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Recombinant Proteins
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Transforming Growth Factor beta
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recombinant human bone morphogenetic protein-2
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Osteocalcin
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Collagen
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Alkaline Phosphatase