Reduction of Osteoclasts in a Critical Embryonic Period Is Essential for Inhibition of Mouse Tooth Eruption

• Published in: Journal of bone and mineral research 2003-01, Vol.18 (1), p.108-116
• Main Authors: Yoshino, Miya, Yamazaki, Hidetoshi, Yoshida, Hisahiro, Niida, Shumpei, Nishikawa, Shin‐Ichi, Ryoke, Kazuo, Kunisada, Takahiro, Hayashi, Shin‐Ichi
• Format: Article
• Language: English
• Subjects: Acid Phosphatase - metabolism; Alveolar Process - cytology; Alveolar Process - embryology; Alveolar Process - growth & development; Animals; Antibodies, Monoclonal - pharmacology; Biological and medical sciences; Diseases of the osteoarticular system; Gestational Age; Incisor - embryology; Incisor - growth & development; Incisor - metabolism; incisor eruption; Isoenzymes - metabolism; macrophage colony‐stimulating factor; Malformations and congenital and or hereditary diseases involving bones. Joint deformations; Medical sciences; Mice; Mice, Inbred C57BL; mouse; osteoclast; Osteoclasts - cytology; Osteoclasts - physiology; osteopetrosis; Receptor, Macrophage Colony-Stimulating Factor - antagonists & inhibitors; Tartrate-Resistant Acid Phosphatase; Tooth Eruption - physiology
• ISSN: 0884-0431; 1523-4681
• DOI: 10.1359/jbmr.2003.18.1.108

Alveolar bone resorption by osteoclasts is essential for tooth eruption. Osteoclast‐deficient Csfmop homozygous (op/op) mice, which lack functional macrophage colony‐stimulating factor (M‐CSF), suffer from osteopetrosis and completely lack tooth eruption. Although osteoclasts appear, and osteopetrosis is cured with age in op/op mice, tooth eruption is never seen. This fact suggests that there is a critical period when osteoclasts are required for tooth eruption. In this study, to detect the critical period, we administered an antagonistic antibody directed against c‐Fms, a receptor for M‐CSF, to inbred C57BL/6 mice for various periods. Administration of this antibody decreased tartrate‐resistant acid phosphatase‐positive (TRAP) osteoclasts, and incisor eruption was completely inhibited by continual administration of this antibody from embryonic day 15.5 (E15.5) until postnatal day 12.5 (D12.5). A 1‐day delay of this administration abolished the inhibition of incisor eruption. The number of TRAP‐positive osteoclasts was significantly reduced between E16.5 and E18.5 in the mice treated with antibody from E15.5 compared with those treated from E16.5. These results indicate that this period, during which the number of osteoclasts decreases significantly, is critical for inhibiting incisor eruption in C57BL/6 mice.