MOLECULAR BIOLOGICAL INVESTIGATION ON DYSUSE BONE ATROPHY CAUSED BY IMMOBILAZATION AND NON-WEIGT BEARING
| Project/Area Number |
11835010
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Institution | TOKYO MEDICAL AND DENTAL UNIVERSITY |
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Principal Investigator |
MORITA Sadao TOKYO MEDICAL AND DENTAL UNIVERSITY, FACULTY OF MEDICINE, ASSOCIATE PROFESSOR, 医学部・付属病院, 助教授 (20202426)
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| Co-Investigator(Kenkyū-buntansha) |
KUMEI Yasuhiro GRADUATE SCHOOL, TOKYO MEDICAL AND DENTAL UNIVERSITY, ASSISTANT PROFESSOR, 大学院・医歯学総合研究科, 講師 (30161714)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,900,000)
Fiscal Year 2000: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1999: ¥2,800,000 (Direct Cost: ¥2,800,000)
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| Keywords | BONE ATROPHY / DYSUSE SYNDROME / WEIGHT BEARING / OSTEOBLAST / CYTOKINE / 骨粗鬆症 / 骨密度 / 無重力 |
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| Research Abstract |
In vitro and in vivo experiments were performed to investigate bone loss mechanism due to long period bed rest, which causes fractures. The right hindlimbs of 5 or 6-week old Wister rats were sciatic/femoral neurectomized, tenotomized or sham operated. The rats were sacrificed 2 weeks after the surgery and the tibiae were removed. pQCT measurement was performed on total, cortical, and trabecular bone separately at different regions. Reduction of the bone mineral density by unloading was observed more significantly at metaphysis than at diaphysis due to histological heterogeneity between metaphysis and diaphysis ; metaphysis is rich in trabecular bone and diaphysis is abundant in cortical bone. Trabecular bone might be more sensitive to unloading because the reduction rate of volumetric bone mineral density in trabecular bone was approximately 10 times and 3 times larger than that of cortical bone in both neurectomy and tenotomy rats, respectively. Unloading also reduced the cross-sectional area and stress strain index at metaphysis. In vitro study was performed by using human primary osteoblast-like cells. Mechanical unloading was created by vector-averaged gravity environment on a clinostat. Cell proliferation was not affected after 4-days exposure to clino-rotation. The amounts of interleukin 6 and interleukin 11 that were produced into medium were not affected by clino-rotation. The levels of prostaglandin E2 in the medium were reduced by clino-rotation. The production of total osteocalcin and gla-osteocalcin into the medium was inhibited by clino-rotation, in concomitant with decreased mRNA levels of osteocalcin gene. However, vitamin K2 counteracted the unloading effects by restoring the rosteocalcin production.
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Report
(3 results)
Research Products
(3 results)
