Energy restriction reduces bone density and biomechanical properties in aged female rats
Energy restriction reduces bone density and biomechanical properties in aged female rats
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DOI：
10.1093/jn/131.9.2382
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发表时间：
2001-09-01
影响因子：
4.2
通讯作者：
Shapses, SA
中科院分区：
文献类型：
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作者：
Talbott, SM;Cifuentes, M;Shapses, SA
骨矿物质密度（BMD）与体重高度相关，体重减轻与BMD降低相关。这种BMD的损失是否会增加骨骼的脆弱性尚不清楚。我们研究了9周的能量限制（ER）对成熟（20周龄，n = 12）和老年（48周龄，n = 16）雌性大鼠的骨密度，矿物质和基质蛋白组成和生物力学性能的影响。能量限制的大鼠比自由进食的对照组少摄入40%的能量。在研究结束时测量骨矿物质含量（灰分和钙含量）和基质蛋白（羟脯氨酸、吡啶交联和蛋白聚糖）、血清激素、部位特异性骨密度和生物力学特性（峰值载荷、峰值扭矩、剪切刚度和弯曲刚度）。在两个年龄组中，与对照组相比，ER使体重降低15 +/- 10%（P < 0.001），股骨骨密度显著降低32-35%（P < 0.01）。能量限制导致老年大鼠胫骨和肱骨密度以及生物力学性能略有降低，但对成年大鼠无显著影响（P < 0.05）。雌激素受体引起的老年大鼠血清胰岛素和雌二醇水平降低（P < 0.05），可能与老年大鼠骨质量改变有关。这些数据表明，尽管由于ER引起的体重减轻对成熟大鼠的一些骨参数是有害的，但只有老年大鼠显示骨密度和生物力学特性的一致降低。
Bone mineral density (BMD) is highly correlated with body weight, and weight loss is associated with reduced BMD. Whether such losses of BMD increase skeletal fragility is unclear. We examined the effect of 9 wk of energy restriction (ER) on bone density, mineral and matrix protein composition and biomechanical properties in mature (20 wk old, n = 12) and aged (48 wk old, n = 16) female rats. Energy-restricted rats were fed 40% less energy than controls that consumed food ad libitum. Bone content of mineral (ash and calcium content) and matrix proteins (hydroxyproline, pyridinium crosslinks and proteoglycans), serum hormones, site-specific bone density and biomechanical properties (peak load, peak torque, shear stiffness and bending stiffness) were measured at the conclusion of the study. In both age groups, ER reduced body weight by 15 +/- 10% (P < 0.001) and dramatically decreased femoral bone density by 32-35% (P < 0.01) compared with controls. Energy restriction resulted in a small reduction in tibia and humerus density, as well as biomechanical properties in the aged but not mature rats (P < 0.05). Reduced serum levels of insulin and estradiol due to ER in aged rats (P < 0.05) may play a role in altering bone quality. These data show that although weight loss due to ER is detrimental to some bone parameters in mature rats, only aged rats show consistent reductions in bone density and biomechanical properties.