| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2012: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2011: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2010: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
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| Research Abstract |
The P6 strain of senescence-accelerated mice (SAMP6) exhibit features of skeletal aging including reduced bone mineral density (BMD), so that various physiological active agents affecting BMD could be examined. We developed the further bone resorption model using water-immersion restraint stress (WRS). Male SAMP6 were divided into three groups, i.e., control group, WRS (6 h/day, 5 times/wk) group, and WRS + vitamin K2 (VK2) (30 mg/kg s.c.) group. SAMP6 were suffered from this stress between 6 to 10 weeks old. BMD was measured using computed tomography (CT) system for small animals, and fluctuation of bone turnover markers and bone histomorphometrical analysis were also performed.BMD of trabecular bone for WRS groups was significantly lower than that of control group, suggesting that WRS was effective to reduce BMD. However, no significant difference of BMD was observed between WRS group and WRS + VK2 group. In bone turnover markers, urinary excretion of CTX, bone resorption mark，was significantly higher in WRS groups than in control. And urinary excretionof calcium was significantly higher in WRS group than in other groups. On the other hand, bone histomorphometrical analysis indicated that trabeculae of WRS showed sthin and mall shape, but that of WRS + VK2 showed larger and round shape. On the resorption area, large osteoclast was observed in WRS, but the number of osteoclasts was significantly decreased in WRS + VK2. These resultsindicated that vitamin K2 could affect bone turnover.
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