Short-Term Exposure to Low-Carbohydrate, High-Fat Diets Induces Low Bone Mineral Density and Reduces Bone Formation in Rats
Short-Term Exposure to Low-Carbohydrate, High-Fat Diets Induces Low Bone Mineral Density and Reduces Bone Formation in Rats
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DOI：
10.1359/jbmr.090813
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发表时间：
2010-02-01
影响因子：
6.2
通讯作者：
Bidlingmaier, Martin
中科院分区：
文献类型：
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作者：
Bielohuby, Maximilian;Matsuura, Maiko;Bidlingmaier, Martin
低碳水化合物、高脂肪(LC-HF)饮食在成人减肥方面很受欢迎，也被用作儿童癫痫治疗的一部分。然而，潜在的风险和副作用仍然存在争议。我们研究了LC-HF饲料对正常饲料(CH，9%脂肪、33%蛋白质和58%碳水化合物)、LC-HF-1(66%脂肪、33%蛋白质和1%碳水化合物)和LC-HF-2(94.5%脂肪、4.2%蛋白质和1.3%碳水化合物)的生长、骨密度(BMD)和周转率的影响。喂食LC-HF饮食的大鼠内脏脂肪和骨髓脂肪积累显著增加，瘦素增加，但胰岛素样生长因子1(IGF-1)减少。两种LC-HF饲料都显著缩短了体长(鼻子到臀部)，但只使用LC-HF-2显著缩短了肱骨、胫骨和股骨的长度。外周定量CT(PQCT)和微型CT(MU CT)分别显示LC-HF组和LC-HF组的胫骨骨密度显著降低，胫骨最大负荷受损。LC-HF组大鼠血清中骨形成标记物I型前胶原N末端前肽减少，而骨吸收标记物CrossLaps无变化。实时定量聚合酶链式反应分析显示，服用LC-HF饮食的大鼠骨髓中影响成骨细胞生成的转录因子(Runx2、Osterix和C/EBP beta)显著减少了70%到80%。总之，两种LC-HF饮食都损害了纵向生长、骨密度和机械性能，这可能是通过减少循环中的IGF-1来调节的。血清骨形成标志物以及影响成骨细胞形成的转录因子的表达减少。这可能表明间充质干细胞分化为成骨细胞的比率较低，从而解释了LC-HF饮食减少骨形成的原因。(C)2010年美国骨与矿物研究学会。
Low-carbohydrate, high-fat (LC-HF) diets are popular for inducing weight loss in adults and are also used as part of a treatment for children with epilepsy. However, potential risks and side effects remain controversial. We investigated effects of LC-HF diets on growth, bone mineral density (BMD), and turnover in growing rats fed for 4 weeks either normal chow (CH, 9% fat, 33% protein, and 58% carbohydrates), LC-HF-1 (66% fat, 33% protein, and 1% carbohydrates), or LC-HF-2 (94.5% fat, 4.2% protein, and 1.3% carbohydrates). Rats fed LC-HF diets accumulated significantly more visceral and bone marrow fat and showed increased leptin but decreased insulin-like growth-factor 1 (IGF-1). Both LC-HF diets significantly decreased body length (nose to rump), but lengths of humerus, tibia, and femur were significantly reduced with LC-HF-2 only. Peripheral quantitative computed tomography (pQCT) and micro-CT (mu CT) independently revealed significant reductions in BMD of tibiae in both LC-HF groups, and tibial maximum load was impaired. Bone-formation marker N-terminal propeptide of type I procollagen was reduced in sera of LC-HF groups, whereas bone resorption marker CrossLaps remained unchanged. Real-time PCR analysis revealed significant reductions by 70% to 80% of transcription factors influencing osteoblastogenesis (Runx2, osterix, and C/EBP beta) in bone marrow of rats fed LC-HF diets. In conclusion, both LC-HF diets impaired longitudinal growth, BMD, and mechanical properties, possibly mediated by reductions in circulating IGF-1. Serum bone-formation markers as well as expression of transcription factors influencing osteoblastogenesis were reduced. This might indicate a lower rate of mesenchymal stem cells differentiating into osteoblasts, thus explaining reduced bone formation with LC-HF diets. (C) 2010 American Society for Bone and Mineral Research.