1993 Fiscal Year Final Research Report Summary
COLLAGEN DEGRADATION MECHANISM IN BONE REMODELING
| Project/Area Number |
04671104
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
畜産学(含草地学)
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| Research Institution | Health Sciences University of Hokkaido |
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Principal Investigator |
YAJIMA Toshihiko , SCHOOL OF DENTISTRY, DEPARTMENT OF ORAL ANATOMY, PROFESSOR, 歯学部, 教授 (10018749)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Bone remodeling / Osteoblast / Collagen phagocytosis / Collagen phagolysosome / Howship's lacunae / Osteoclast |
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| Research Abstract |
Cells consisted bone tissue are osteoblasts, osteocytes, osteoclasts and their precursir cells. Bone remodeling takes place by those cell link system. The degradation of mineralized bone matrix by active osteoclasts is censiderd to be primarily due to a combination of focal decalcification by organic acids building up under the ruffled borders of osteoclasts and extracellular digestion by acid hydrolase liberated by exocytosis at such borders. However, it has not been known percise mechanism of collagen degradation of bone matrix at remodeling sites.
The present study was undertaken to examine the collagenolytic actibity of osteoblasts and osteoblastic cells on periodontal ligament-alveolar bone interface of rat molars, and cultured osteoblastic cells (MC3TC-E1) by electron microscopy. Osteoblast-like cells located beside osteoclasts and osteoblasts adjacent to the osteoid on periodontal ligament-bone interface phagocytosed collagen fibrils and cntained several collagen-containg phagosomes. Fibroblasts phagocytosed and degraded collagen dibeils at bone remodeling sites. Additionally, MC3T2-E1 cells cultured in plastic dishes also engulfed collagen fibrlls and had collagencontaining phagosomes. ACPase reaction products were prerent in these collagen-containing phagolysosomes. Collagen fibrils within the phagolysosomes demonstrated various stage of degradation. Residual bodies containg still reconzable banded collagen fibrils were observed synthesizing and disintegration of collagen.
Our results suggest that osteoblasts and osteoblastic cells may play the important role in the bone remodeling and metabolic breakdown of the collagen.
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