1992 Fiscal Year Final Research Report Summary
Type X collagen gene expression during formation of primary bone marrow in the endochondral bone
| Project/Area Number |
03670176
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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 |
Experimental pathology
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| Research Institution | KUMAMOTO UNIVERSITY |
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Principal Investigator |
IYAMA Ken-ichi Department of Neuroscience and Immunology, Division of Developmental Neurobiology, Kumamoto University Graduate School of Medical Sciences; Associate Professor, 医学部, 助教授 (10040536)
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| Co-Investigator(Kenkyū-buntansha) |
KITAOKA Mitsuhiko Department of Neuroscience and Immunology, Division of Developmental Neurobiolog, 医学部, 助手 (30117345)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Type X collagen / Endochondral bone / Osteoblast / Chondrocyte / Bone marrow / Periosteal cell / Heterotopic bone / Calcification |
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| Research Abstract |
Type X collagen is synthesized by hypertrophic chondrocytes of the growth plate and deposited in the calcifying region, while type II collagen is synthesized by resting and proliferating chondrocytes. We examined the spatiotemporal localization of collagen type I, II and X mRNAs in embryonic chick vertebrae undergoing endochondral ossification, and also demonstrated an atypical expression of collagen type X gene in the heterotopic endochondral bone induced by chick periosteal allografts using in situ hybridization. In the embryonic chick vertebra a stage 45, a reversed pattern of distribution between collagen type II and type X mRNAs was noted in maturing chondrocyte zones. High signals of collagen type I mRNA were restricted in osteoblasts derived from periosteal mesenchymal cells. Primary bone marrow rapidly developed in the area in which type X collagen was deposited. On the other hand, different expressions of these collagen mRNAs were observed in the heterotopic endochondral bone of the subcutaneously grafted periosteum. Five days after transplantation, developing non-hypertrophic chondrocytes with rapid expression of collagen type X mRNA were identified in the mass of atypical cartilage. At day 9 after transplantation, sparsely distributed chondrocytes having high signals of collagen type x mRNA were demonstrated in osteoid and/or woven bone.
The phenotype of chondrocyte showing rapid expression of collagen type X gene derived from undifferentiated periosteal mesenchymal cells seems to participate in the primary bone marrow formation and in the early stage of fracture repair.
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