| Project/Area Number |
17591924
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Morphological basic dentistry
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| Research Institution | Showa University |
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Principal Investigator |
MAYAHARA Mitsuori (2006) Showa University, School of Dentistry, Research Associate, 歯学部, 助手 (30384184)
佐々木 崇寿 (2005) 昭和大学, 歯学部, 教授 (50129839)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAHASHI Naoyuki Matsumoto Dental University, Institute for Dental Science, Professor, 大学院歯学独立研究科, 教授 (90119222)
TAKAMI Masamichi Showa University, School of Dentistry, Assistant Professor, 歯学部, 講師 (80307058)
石浦 美帆 昭和大学, 歯学部, 助手 (40327937)
馬谷原 光織 昭和大学, 歯学部, 助手 (30384184)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 2006: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2005: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | gene / cell・tissue / oral histology / pathology / bone metabolomics / 破骨細胞 / オステオプロテゲリン / OPG遺伝子欠損マウス / 骨粗鬆症 / 歯周病 / 細胞培養 / 免疫組織化学 / 電子顕微鏡 |
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| Research Abstract |
Osteoprotegerin (OPG)-deficient mice exhibit severe bone loss including the destruction of growth plate cartilage. Using OPG-deficient mice, we attempted to clarify the differentiation and ultrastructure of osteoclasts located on the destroyed growth plate cartilage and trabecular bone matrix in long bones. In (-/-) homozygous OPG knockout mice, adjacent to the growth plate cartilage, the formation of bone trabeculae without a calcified cartilaginous core resulted in an irregular chondrocyte distribution in the growth plate cartilage. At the metaphyseal ossification center, TRAP-positive osteoclasts showed unusual localization on both type-II collagen-positive cartilage and type-I collagen-positive bone matrix. Osteoclasts located on cartilage matrix lacked a typical ruffled border structure, but formed resorption lacunae. During growth plate cartilage destruction, osteoclasts formed ruffled border structures on bone matrix deposited on the remaining cartilage surfaces. These findings suggest that, in OPG (-/-) mice, osteoclast structure differs, depending on the matrix of either cartilage or bone. Then, we examined the effects of OPG administration on the internal trabecular bone structure and osteoclast differentiation in OPG (-/-) mice. OPG administration to OPG (-/-) mice significantly inhibited trabecular bone loss and maintained the internal trabecular bone structure, but did not reduce the osteoclast number on bone trabeculae. For most osteoclasts, OPG administration caused disappearance or reduction of the ruffled border, but induced neither necrotic nor apoptotic damages. These results suggest that OPG administration is an effective means of maintaining the internal structure and volume of trabecular bone in metabolic bone diseases by inhibition of osteoclastic bone resorption.
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