1988 Fiscal Year Final Research Report Summary
Ultrastructure of bone resorption by osteoclasts
| Project/Area Number |
62570808
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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 |
Morphological basic dentistry
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
MITSUTERU Hosoi Hiroshima University, Associate Professor, 歯学部, 助教授 (00034190)
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| Co-Investigator(Kenkyū-buntansha) |
TOSHITAKA Akisaka Asahi University, Professor, 歯学部, 教授 (70116523)
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| Project Period (FY) |
1987 – 1988
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| Keywords | Quick freezing / Freeze-substitution / Osteoclast / Freeze-fracture / 酸性フォスファターゼ / 膜内粒子 / 前破骨細胞 |
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| Research Abstract |
The main purpose of the present study was to pursue the native state of in vivo osteoclasts in chick metaphyseal bone at electron microscopic level. Three different methods were employed in the present research: (1) quick freezing and freeze-substitution, (2) freeze-replica and (3) cytochemical methods.
Quick freezing and substitution method ahowed several unreported results that the ruffled border was supported with the undercoat material, whereas the clear zone and baso-lateral membrane were devoid of it. One of the interesting finding was that cementing materials was observed between the clear zone membrane and the surface of calcified matrix. The combination of freeze substitution and saponin detergent visualized us the cytoskeletal components of osteoclasts. We clarified the ultrastructural difference among the ruffled border, clear zone and other cytoplasm after quick freezing. The ruffled border contained densely packed and disorganized microfilament meshwork. The results as ment
… More
ioned above was appeared in Anatomical Record (vol.224, pp.323-332, 1988).
Freeze-replicas showed a remarkable differences among ruffled border, clear zone, baso-lateral and intracytoplasmic membranes in the shape, intensity, and pattern of intramembtanous particles (IMPS). The number and pattern of IMPs in ruffled border membrane was dramatically changed from attached to detached osteoclasts. Our observations indicate that IMPs was synchronized with cell activity. We are now planning to submit the results obtained by freeze-replicas to some anatomical or bone journals.
The results of our cytochemical study was appeared in Cell ＆ Tis Res (vol. 255, pp.69-76, 1989) in which tartrate resistant acid phoshatase (ACPase) activity was detected within biosynthetic pathway of osteoclasts and the surface layer of resorpted bone. Presteoclast showed similar localization pattern to the mature osteoclasts. This type of ACPase identified a family of osteoclast from other cells.
From our study it becomes evident that freezing methods are very valuable and inevitable for the morphological study of calcified tissues. Our study provided new information of in vivo osteoclast ultrastructure. Less
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