Department of Health Sciences, University of Jyväskylä, P.O. Box 35 (LL), 40014 Jyväskylä, Finland.
Calcif Tissue Int. 2010 May;86(5):411-9. doi: 10.1007/s00223-010-9346-3. Epub 2010 Mar 13.
Both physical activity and body mass affect bone properties. In this study we examined how diet-induced obesity combined with voluntary physical activity affects bone properties. Forty 7-week-old male C57BL/6J mice were assigned to four groups evenly: control diet (C), control diet + running (CR), high-fat diet (HF, 60% energy from fat), and high-fat diet + running (HFR). After 21-week intervention, all mice were killed and the left femur was dissected for pQCT and mechanical measurements. Body mass increased 80% in HF and 62% in HFR, with increased epididymal fat pad weight and impaired insulin sensitivity. Except for total and trabecular volumetric bone mineral density (BMD), bone traits correlated positively with body mass, fat pad, leptin, and osteoprotegerin. Obesity induced by a high-fat diet resulted in increased femoral bone cross-sectional area, mineral content (BMC), polar moment of inertia, and mechanical parameters. Of the mice accessing the running wheel, those fed the control diet had thinner cortex and less total metaphyseal BMC and BMD, with enlarged metaphyseal marrow cavity, whereas mice fed the high-fat diet had significantly higher trabecular BMD and smaller marrow cavity. However, the runners had a weaker femoral neck as indicated by decreased maximum flexure load. These results suggest that voluntary running exercise affects bone properties in a site-specific manner and that there is a complex interaction between physical activity and obesity. Thus, both diet and exercise should be considered when optimizing the effects on body composition and bone, even though the underlying mechanisms remain partly unknown.
身体活动和体重都会影响骨骼特性。在这项研究中，我们研究了饮食诱导的肥胖与自愿身体活动相结合如何影响骨骼特性。将 40 只 7 周龄雄性 C57BL/6J 小鼠平均分配到四组：对照饮食（C）、对照饮食+跑步（CR）、高脂肪饮食（HF，脂肪提供 60%能量）和高脂肪饮食+跑步（HFR）。经过 21 周的干预后，所有小鼠被处死，取左侧股骨进行 pQCT 和力学测量。HF 组体重增加了 80%，HFR 组增加了 62%，附睾脂肪垫重量增加，胰岛素敏感性受损。除了总骨和小梁体积骨密度（BMD）外，骨骼特征与体重、脂肪垫、瘦素和护骨素呈正相关。高脂肪饮食引起的肥胖导致股骨横截面积、矿物质含量（BMC）、极惯性矩和力学参数增加。在使用跑步轮的小鼠中，喂食对照饮食的小鼠皮质较薄，总干骺端 BMC 和 BMD 减少，干骺端骨髓腔增大，而喂食高脂肪饮食的小鼠的小梁 BMD 显著增加，骨髓腔较小。然而，跑步者的股骨颈较弱，表现为最大弯曲负荷降低。这些结果表明，自愿跑步运动以特定部位的方式影响骨骼特性，并且身体活动和肥胖之间存在复杂的相互作用。因此，即使其潜在机制部分未知，在优化身体成分和骨骼的效果时，应同时考虑饮食和运动。
