title: Difference between dogs and rats with regard to osteoclast-like cells in calcium-deficient hydroxyapatite-induced osteoinduction.
abstract: Material-induced osteoinduction is reported in comparatively large animals such as dogs and pigs; however, it does not often occur in small animals such as rodents. In this study, we implanted porous calcium-deficient hydroxyapatite (CDHA) in the dorsal muscles of dogs and rats and compared the two species, with emphasis on multinucleated cells, by using hematoxylin and eosin (HE) staining, tartrate-resistant acid phosphatase (TRAP) staining, transmission electron microscope (TEM) observation, and reverse transcription-polymerase chain reaction (RT-PCR). In CDHA extracted from dogs, numerous TRAP-positive multinucleated cells were detected after 2 weeks and new bone formation was observed after 4 weeks. In contrast, in rats, only a small number of TRAP-positive cells were detected and no bone formation was observed within 6 weeks. CDHA was more degraded in dogs than in rats. TEM observation of the multinucleated cells in CDHA extracted from dogs after 3 weeks revealed osteoclast-like features such as ruffled borders. However, CDHA extracted from rats did not exhibit osteoclast-like features. RT-PCR evaluation showed that the expression of cathepsin K was higher in dogs than in rats. These results indicate that TRAP-positive cells might be one of the main factors responsible for the cross-species difference in material-induced osteoinduction.
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, Shogoin, Kawahara-cho 54, Sakyo-ku, Kyoto 606-8507, Japan. akiyama@kuhp.kyoto-u.ac.jp
authors.forename: Norihiro
authors.initials: N
authors.lastname: Akiyama
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Takemoto
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Fujibayashi
authors.forename: Masashi
authors.initials: M
authors.lastname: Neo
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hirano
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakamura
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D002452:Cell Count; D004285:Dogs; D017886:Durapatite / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D015726:Giant Cells / Q000166:cytology / Q000187:drug effects / Q000648:ultrastructure; D020007:Implants, Experimental; D007527:Isoenzymes / Q000378:metabolism; D010010:Osteoclasts / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology / Q000648:ultrastructure; D010012:Osteogenesis / Q000187:drug effects* / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000071681:Tartrate-Resistant Acid Phosphatase; D014961:X-Ray Diffraction; D055114:X-Ray Microtomography
chemical_list: D007527:Isoenzymes; D017886:Durapatite; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase