| Project/Area Number |
61440077
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Functional basic dentistry
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| Research Institution | Tokyo Medical and Dental University |
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Principal Investigator |
OGURA Hideaki Professor, Faculty of Dentistry, Tokyo Medical and Dental University, 歯学部, 教授 (20013831)
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| Co-Investigator(Kenkyū-buntansha) |
KASUGAI Shohei Instructor, Faculty of Dentistry, Tokyo Medical and Dental Dniversity, 歯学部, 助手 (70161049)
MATAKI Shiro Lecturer, Faculty of Dentistry, Tokyo Medical and Dental University, 歯学部, 講師 (80157221)
OHYA Keiichi Associate Professor, Faculty of Dentistry, Tokyo Medical and Dental University, 歯学部, 助教授 (10126211)
NISHIMURA Yoshie Research Associate, Faculty of Dentistry, Tokyo Medical and Dental University
西村 佳恵 東京医科歯科大学, 歯学部, 技官(教務職員)
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| Project Period (FY) |
1986 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥16,000,000 (Direct Cost: ¥16,000,000)
Fiscal Year 1988: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1987: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1986: ¥12,000,000 (Direct Cost: ¥12,000,000)
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| Keywords | Low-Calcium Diet / Alveolar Bone / Bone Resorption / Osteoclast / Parathyroid Hormone / 歯槽骨吸収動物実験モデル / 形態計測 / 細胞運動 / パラサイロイドホルモン / カルシトニン / 歯槽骨吸収病態モデル / 歯槽骨吸収 / 血漿カルシウム / 血漿イオン化カルシウム / 血漿アルカリフォスファターゼ |
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| Research Abstract |
The present study was carried out to investigate the mechanism of alveolar bone resorption with special reference to the process of bone resorption induced by a low calcium diet and to the isolated osteoclasts under the in vitro culture condition. Male Wistar rat were either fed a low Ca diet (0.05% Ca, 0.35% P) or a control diet (0.5% Ca, 0.35% P) by using a pair feeding technigue. The biochemical parameters in blood and the morphological changes in alveolar bone were examined during the experimental period of 20 days. Osteoclasts were isolated and cultured from bone marrow of rat tibia. The histochemical properties and the cell motility in culture condition of these isolated osteoclasts were investigated. The following results were obtained from the experiments.
1. In rats fed a low Ca diet, the bone area significantly reduced at day 3 and progressively decreased to about half of the controls by the end of the experiment.
2. The bone resorption was obvious in the cancellous bone during
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the early experimental period and then the cortical bone was resorbed. However, the contour of alveolar bone and the bone apposition rate did not change.
3. The alveolar bone propre which surrounds the tooth socket could hardly be resorbed. This finding suggested a possibility that there may exist the preservation mechanism for alveolar bone proper against bone resorption in order to support the occlusion force transmitted by the tooth.
4. The number of osteoclasts increased in the cancellous bone and cortical bone, whereas fairly be constant in the tooth socket. The increase in number of osteoclasts matched to the rise of parathyroid hormone (PTH) level in blood, indicating that the alveolar bone resorption may be started by the elevated PTH.
5. Isolated osteoclasts at least maintained their viability within 24 hrs in culture used in the present study.
6. Isolated osteoclasts showed the higher activity of tartrate-resistant acid phosphatase. However since the other cell showed the activity even in the high concentration of tartrate, this enzyme activity could not be used as a special marker of the osteoclasts in rat.
7. Isolated osteoclasts moved on the culture dish by spreading either the lamelliopodia or the filopodia. Calcitonin treatment reduced their motility.
8. The motility of the isolated osteoclasts was reduced when they were cultured on the collagen coated dish. Collagen seems to inhibit the bone resorbing activity of the osteoclasts. From these results, the alveolar bone resorption may quite related to the mechanical forces induced by the occlusal function of the tooth. Further, the study of the motility of osteoclasts seems to be important in the alveolar bone resorption. Less
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