| Project/Area Number |
04454454
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Morphological basic dentistry
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| Research Institution | Showa University |
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Principal Investigator |
YOSHIKI Shusaku Showa Univ.Sch.of Dentistry, Professor, 歯学部, 教授 (30085740)
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| Co-Investigator(Kenkyū-buntansha) |
YOKOSE Satoshi Showa Univ.Sch.of Dentistry, Research Assoc., 歯学部, 助手 (90245803)
IKEDA Tohru Showa Univ.Sch.of Dentistry, Assistant Prof., 歯学部, 講師 (00211029)
YAMAGUCHI Akira Showa Univ.Sch.of Dentistry, Associate Prof., 歯学部, 助教授 (00142430)
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| Project Period (FY) |
1992 – 1993
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| Project Status |
Completed (Fiscal Year 1993)
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| Budget Amount *help |
¥6,800,000 (Direct Cost: ¥6,800,000)
Fiscal Year 1993: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1992: ¥5,100,000 (Direct Cost: ¥5,100,000)
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| Keywords | bone / osteoblast / aiging / cell culture / bone matrix / gene expression |
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| Research Abstract |
To investigate the mechanism involved in the changes in bone tissues associated with aging, we conducted the following experiments.
1)Age-related reduction in bone matrix protein mRNA in rat bone tissue
Age-related changes in the expression of bone matrix protein mRNAs in individual osteoblastic cells were analyzed in vivo by in situ hybridization using undecalcified bone sections. In the femurs of 8-week-old male rats, strong expression of type I collagen and osteocalcin mRNAs was detected in cuboidal osteoblasts on the bone surface. Osteopontin mRNA was detected in some of the mononuclear cells and osteoclasts on the bone resorption surface. In the femurs of 60-week-old and 100-week-old male rats, expression these bone matrix protein mRNAs was markedly decreased. These results indicate age-related reductions in both biological activity and numbers of osteoblasts.
Properties of osteoprogenitor cells in bone marrow of aged rats
To investigate the mechanism of bone loss associated woth aging, we examined the properties of rat bone marrow cells including Colony Forming Unit-Fibroblastic (CFU-F) which contains osteoprogenitor cells. The following results were obtained.
1)Both alkaline phosphatase (ALP) activity and parathyroid hormone response in bone marrow cells were decreased with age. 2) Both the total number of CFU-F and the ALP-positive CFU-F were decreased with age. 3) Nine out of 10 CFU-Fs isolated from 4-week-old rats form bone-like tissues when they were transplanted into rat peritoneal cavity using diffusion chambers. However, only 3 out of 6 CFU-Fs isolated from 60-week-old rats form bone-like tissues. These results suggest that decrease in number of osteoprogenitor cells is involed, at least in part, in the mechanizm of senile osteoporosis.
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