title: Enhancement of crude bone morphogenetic protein-induced new bone formation and normalization of endochondral ossification by bisphosphonate treatment in osteoprotegerin-deficient mice.
abstract: Osteoprotegerin (OPG) is a novel secreted member of the tumor necrosis factor receptor family which plays a crucial role in negative regulation of osteoclastic bone resorption. We investigated both the quantity and quality of heterotopic new bone induced by crude bone morphogenetic protein (BMP) as a means of examining bone metabolism by bisphosphonate administration in OPG-/- mice. Four weeks after implantation of crude BMP, the volume of heterotopic new bone in OPG-/- mice without alendronate was significantly less than in wild-type (WT) mice. Alendronate treatment of OPG-/- mice resulted in enhancement of the volume of heterotopic new bone. Histological findings revealed that WT mice showed normal bone formation with persistent cartilage that was interspersed with islands of bone. In contrast, the cartilage was replaced by trabecular bone and bone marrow adipocytes in OPG-/- mice without alendronate. However, some cartilage was still present in OPG-/- mice with alendronate compared to those without alendronate. All bone formation-related parameters and bone resorption-related parameters were significantly lower in OPG-/- mice with alendronate than in those without alendronate. These findings suggest that in stimulated osteoclastogenesis without OPG, osteoinductive activity induced by crude BMP is inhibited and endochondral ossification induced by crude BMP is accelerated. On the other hand, alendronate treatment of OPG-/- mice caused osteoinductive activity induced by crude BMP to increase and endochondral ossification induced by crude BMP to be decelerated. In conclusion, inhibition of stimulated osteoclastogenesis results in the enhancement of new bone formation and normalization of endochondral ossification.
authors.affiliation: Department of Orthodontics, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan. machako@dpc.aichi-gakuin.ac.jp
authors.forename: M
authors.initials: M
authors.lastname: Tabuchi
authors.forename: K
authors.initials: K
authors.lastname: Miyazawa
authors.forename: M
authors.initials: M
authors.lastname: Kimura
authors.forename: H
authors.initials: H
authors.lastname: Maeda
authors.forename: T
authors.initials: T
authors.lastname: Kawai
authors.forename: Y
authors.initials: Y
authors.lastname: Kameyama
authors.forename: S
authors.initials: S
authors.lastname: Goto
mesh_terms: D019386:Alendronate / Q000494:pharmacology*; D000469:Alkaline Phosphatase / Q000097:blood; D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000737:chemistry / Q000494:pharmacology*; D001862:Bone Resorption / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism; D002417:Cattle; D020219:Chondrogenesis / Q000187:drug effects* / Q000235:genetics; D004195:Disease Models, Animal; D004357:Drug Synergism; D005260:Female; D006023:Glycoproteins / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D007279:Injections, Subcutaneous; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009999:Ossification, Heterotopic / Q000139:chemically induced / Q000473:pathology; D010006:Osteoblasts / Q000187:drug effects / Q000473:pathology; D010010:Osteoclasts / Q000187:drug effects / Q000473:pathology; D010012:Osteogenesis / Q000187:drug effects* / Q000235:genetics; D010024:Osteoporosis / Q000097:blood / Q000188:drug therapy / Q000235:genetics; D053244:Osteoprotegerin; D018160:Receptors, Cytoplasmic and Nuclear / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D018124:Receptors, Tumor Necrosis Factor / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism
chemical_list: D019485:Bone Morphogenetic Proteins; D006023:Glycoproteins; D053244:Osteoprotegerin; D018160:Receptors, Cytoplasmic and Nuclear; D018124:Receptors, Tumor Necrosis Factor; C506031:Tnfrsf11b protein, mouse; D000469:Alkaline Phosphatase; D019386:Alendronate