| Project/Area Number |
10470415
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
補綴理工系歯学
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| Research Institution | OKAYAMA UNIVERSITY |
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Principal Investigator |
KUBOKI Takuo Okayama University, Dental Hospital, Lecture, 歯学部・附属病院, 講師 (00225195)
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| Co-Investigator(Kenkyū-buntansha) |
HATTORI Takako Okayama University, Dental School, Research Associate, 歯学部, 助手 (00228488)
TAKIGAWA Masaharu Okayama University, Dental School, Professor, 歯学部, 教授 (20112063)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥11,300,000 (Direct Cost: ¥11,300,000)
Fiscal Year 1999: ¥7,100,000 (Direct Cost: ¥7,100,000)
Fiscal Year 1998: ¥4,200,000 (Direct Cost: ¥4,200,000)
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| Keywords | Chondrocyte / Cartilage Degradation Factors / Cyclic Mechanical Stress / Matrix Metalloproteinases / Interleukin-1 / Proteoglycan / インターロイキン-1 / 機械的負荷 / 周期的負荷 / マトリックスメタロプロテアーゼ |
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| Research Abstract |
To clarify the mechanism of cartilage degradation induced by mechanical stress, we investigated the influence of cyclic tension force (CTF) on the metabolism of cultured chondrocytes, The chondrocytes were exposed to CTF by using Flexercell strain unit. Five or 15 kPa of high frequency CTF significantly inhibited the syntheses of DNA, proteoglycan, collagen and protein. Fifteen kPa of high frequency CTF induced the expression of interleukin-1 (IL-1), matrix metalloproteinase (MMP)-2 and -9 mRNA, and increased the production of pro-and active-Mmp-9. the degradation of proteoglycan was inhibited by MMP Inhibitor, indicating that MMPs are involved in the degradation of proteoglycan induced by high frequency CTF.
Moreover reducing the frequency of CTF from high to low decreased the inhibition of proteoglycan synthesis. These findings suggest that the CTF frequency is one of the key determinants of the chondrocyte metabolism. Low magnitude CTF, whether high or low frequency, did not cause the gene expression of cartilage degradation factors, suggesting that this magnitude of CTF causes only minor change of cartilage matrix. High magnitude and frequency CTF caused the gene expression of IL-1 and MMP-9, followed by increases in the production of MMP-2 and -8 protein suggest that excessive and continuous cyclic mechanical stress induces the production of IL-1 and MMP-9, resulting in cartilage degradation.
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