Styner Maya, Thompson William R, Galior Kornelia, Uzer Gunes, Wu Xin, Kadari Sanjay, Case Natasha, Xie Zhihui, Sen Buer, Romaine Andrew, Pagnotti Gabriel M, Rubin Clinton T, Styner Martin A, Horowitz Mark C, Rubin Janet
Department of Medicine, University of North Carolina, Chapel Hill, NC, USA.
Department of Medicine, University of North Carolina, Chapel Hill, NC, USA.
Bone. 2014 Jul;64:39-46. doi: 10.1016/j.bone.2014.03.044. Epub 2014 Apr 5.
Marrow adipose tissue (MAT), associated with skeletal fragility and hematologic insufficiency, remains poorly understood and difficult to quantify. We tested the response of MAT to high fat diet (HFD) and exercise using a novel volumetric analysis, and compared it to measures of bone quantity. We hypothesized that HFD would increase MAT and diminish bone quantity, while exercise would slow MAT acquisition and promote bone formation. Eight week-old female C57BL/6 mice were fed a regular (RD) or HFD, and exercise groups were provided voluntary access to running wheels (RD-E, HFD-E). Femoral MAT was assessed by μCT (lipid binder osmium) using a semi-automated approach employing rigid co-alignment, regional bone masks and was normalized for total femoral volume (TV) of the bone compartment. MAT was 2.6-fold higher in HFD relative to RD mice. Exercise suppressed MAT in RD-E mice by more than half compared with RD. Running similarly inhibited MAT acquisition in HFD mice. Exercise significantly increased bone quantity in both diet groups. Thus, HFD caused significant accumulation of MAT; importantly running exercise limited MAT acquisition while promoting bone formation during both diets. That MAT is exquisitely responsive to diet and exercise, and its regulation by exercise appears to be inversely proportional to effects on exercise induced bone formation, is relevant for an aging and sedentary population.
与骨骼脆弱和血液学功能不全相关的骨髓脂肪组织（MAT），目前仍了解甚少且难以量化。我们使用一种新型体积分析方法测试了MAT对高脂饮食（HFD）和运动的反应，并将其与骨量测量结果进行比较。我们假设高脂饮食会增加MAT并减少骨量，而运动则会减缓MAT的积累并促进骨形成。将8周龄的雌性C57BL/6小鼠分为常规饮食组（RD）或高脂饮食组，运动组小鼠可自愿使用跑步轮（RD-E、HFD-E）。采用刚性共配准、区域骨掩膜的半自动方法，通过μCT（脂质结合锇）评估股骨MAT，并将其标准化为骨腔的总股骨体积（TV）。与RD小鼠相比，HFD小鼠的MAT高2.6倍。与RD组相比，运动使RD-E小鼠的MAT减少了一半以上。跑步同样抑制了HFD小鼠的MAT积累。运动显著增加了两个饮食组的骨量。因此，高脂饮食导致MAT显著积累；重要的是，跑步运动在两种饮食期间都限制了MAT的积累，同时促进了骨形成。MAT对饮食和运动具有高度敏感性，并且运动对其的调节似乎与对运动诱导的骨形成的影响成反比，这对于老龄化和久坐不动的人群具有重要意义。
