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Collagen Degradation and Remodeling at the Alveolar Bone-Ligament Interface.

Research Project

Project/Area Number 11671807
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Morphological basic dentistry
Research InstitutionHealth Science University of Hokkaido

Principal Investigator

YAJIMA Toshihiko  Health Science University of Hokkaido, School of Dentistry, Professor, 歯学部, 教授 (10018749)

Co-Investigator(Kenkyū-buntansha) EICHI Tsuruga  Health Science University of Hokkaido, School of Dentistry, Assistant Professor, 歯学部, 助手 (30295901)
IRIE Kazuharu  Health Science University of Hokkaido, School of Dentistry, Associate Professor, 歯学部, 講師 (70223352)
Project Period (FY) 1999 – 2000
Project Status Completed (Fiscal Year 2000)
Budget Amount *help
¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2000: ¥900,000 (Direct Cost: ¥900,000)
Keywordsalveolar bone / osteoblast / collagen phagocytosis / osteocytes / acid phosphatase / tartrate-resistant acid phosphatase / periodontium / bone remodeling / コラーゲン貧食 / 細胞内コラーゲン消化 / カテプシン
Research Abstract

The collagen-phagocytosing activity of osteoblasts at the alveolar bone-ligament interface of rat mandibular first molars was investigated both histologically and histochemically. Alveolar bones of male Wister rats were used in this study. Collagen-containing phagosomes appeared in cuboidal osteoblasts aligned on the bone surface. The 5.7% of the osteoblasts exhibiting alkaline phosphatase activity revealed collagen-containing phagosomes. In addition, acid phosphatase activity and immunocytochemical distribution of cathepsin B were found in these collagen-containing phagosomes at similar locations. The presence of both enzymes in the phagosomes suggests that an intracellular degradation of collagen occurs. Therefore, in addition to the osteoblastic functions of synthesizing and secreting bone matrices, osteoblasts are also capable of phagocytosis and the intracellular disintegration of collagen. Our findings suggest that osteoblasts at the alveolar bone-periodontal ligament interface h … More ave a collagen-phagocytosing ability and play an important role in the physiological remodeling and metabolic breakdown of collagen fibrils of periodontal ligament without osteoclastic bone remodeling.
Based on their ultrastructural features, osteocytes have been classified into formative-, resorptive-, and degenerative-phase. However, the mechanism of the morphological changes from formative osteocytes to resorptive osteocytes is still unclear. Therefore, we examined the histochemical changes in osteocytes from two distinct areas in the mandibles, focusing on the relationship between osteocytes and osteoclastic bone resorption. Tartrate-resistant acid phosphatase (TRAP) activity was detected only in osteocytes located near sites of osteoclastic bone resorption. Osteocytes far from osteoclasts lacked TRAP activity, even those that had been enclosed in bone matrix as long as the osteocytes that did show TRAP activity. Furthermore, glycogen granules in osteocytes disappeared when the cell acquired TRAP activity. These findings suggest that the acquisition of TRAP activity in an osteocytes is closely synchronized with bone resorption. Disappearance of glycogen in osteocytes in the same area may also be related to the acquisition of TRAP activity or bone resorbing activity. The osteocytes characterized by glycogen accumulation must be in the phase that follows the formative phase, in which osteocytes display neither formation nor resorption activity. Less

Report

(3 results)
  • 2000 Annual Research Report   Final Research Report Summary
  • 1999 Annual Research Report
  • Research Products

    (7 results)

All Other

All Publications (7 results)

  • [Publications] Yajima T: "Collagen-phagocytosing ability of periodontal osteoblasts at the bone surface."Arch Histol Cytol. 62. 17-25 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] Irie K: "The histochemical and cytochemical changes from formative to resorptive osteocytes."Acta Histochem Cytochem. 33. 385-391 (2000)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] Yajima T, Sakakura Y, Tsuruga E, Hirai T, Ikeda Y, Fujii S, Shide N: "Collagen-phagocytosing ability of periodontal osteoblasts at the bone surface"Arch Gistol Cytol. 62. 17-25 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] Irie K, Ozawa H, Yajima T: "The histochemical and Cytochemical changes from formative to resorptive osteocytes"Acta Histochem Cytochem. 33. 385-391 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] Yajima T,Sakakura Y,Tsuruga et al.: "Collagen-phagocytosing ability of periodontal osteoblasts at the bone surface."Arch Histol Cytol. 62. 17-25 (1999)

    • Related Report
      2000 Annual Research Report
  • [Publications] Irie K,Ozowa H,Yajima T: "The histochemical and cytochemical changes from formative to resorptive osteocytes."Acta Histochem Cytochem. 33. 385-391 (2000)

    • Related Report
      2000 Annual Research Report
  • [Publications] Yajima,T.et al.: "Collagen-phagocytosing ability of periodontal osteoblasts at the bone surface."Arch.Histol.Cytol.. 62. 17-25 (1999)

    • Related Report
      1999 Annual Research Report

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Published: 2000-04-01   Modified: 2016-04-21  

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