Viguet-Carrin S, Hoppler M, Membrez Scalfo F, Vuichoud J, Vigo M, Offord E A, Ammann P
Centre de Recherche Nestlé, Vers-chez-les-Blanc, 1000 Lausanne 26, Switzerland.
Centre de Recherche Nestlé, Vers-chez-les-Blanc, 1000 Lausanne 26, Switzerland.
Bone. 2014 Nov;68:85-91. doi: 10.1016/j.bone.2014.07.029. Epub 2014 Aug 4.
In this study we investigated the effect of supplementing the diet of the growing male rat with different levels of calcium (from low to higher than recommended intakes at constant Ca/P ratio), on multiple factors (bone mass, strength, size, geometry, material properties, turnover) influencing bone strength during the bone accrual period. Rats, age 28days were supplemented for 4weeks with high Ca (1.2%), adequate Ca (0.5%) or low Ca level (0.2%). Bone metabolism and structural parameters were measured. No changes in body weight or food intake were observed among the groups. As anticipated, compared to the adequate Ca intake, low-Ca intake had a detrimental impact on bone growth (33.63 vs. 33.68mm), bone strength (-19.7% for failure load), bone architecture (-58% for BV/TV) and peak bone mass accrual (-29% for BMD) due to the hormonal disruption implied in Ca metabolism. In contrast, novel, surprising results were observed in that higher than adequate Ca intake resulted in improved peak bone strength (106 vs. 184N/mm for the stiffness and 61 vs. 89N for the failure load) and bone material properties (467 vs. 514mPa for tissue hardness) but these effects were not accompanied by changes in bone mass, size, microarchitecture or bone turnover. Hormonal factors, IGF-I and bone modeling were also evaluated. Compared to the adequate level of Ca, IGF-I level was significantly lower in the low-Ca intake group and significantly higher in the high-Ca intake group. No detrimental effects of high Ca were observed on bone modeling (assessed by histomorphometry and bone markers), at least in this short-term intervention. In conclusion, the decrease in failure load in the low calcium group can be explained by the change in bone geometry and bone mass parameters. Thus, improvements in mechanical properties can be explained by the improved quality of intrinsic bone tissue as shown by nanoindentation. These results suggest that supplemental Ca may be beneficial for the attainment of peak bone strength and that multiple factors linked to bone mass and strength should be taken into account when setting dietary levels of adequate mineral intake to support optimal peak bone mass acquisition.
在本研究中，我们调查了在生长期雄性大鼠的饮食中补充不同水平钙（从低到高于推荐摄入量，钙磷比例恒定）对骨量增加期影响骨强度的多个因素（骨量、强度、大小、几何形状、材料特性、骨转换）的作用。28日龄的大鼠分别用高钙（1.2%）、适量钙（0.5%）或低钙水平（0.2%）补充4周。测量骨代谢和结构参数。各组之间未观察到体重或食物摄入量的变化。正如预期的那样，与适量钙摄入相比，低钙摄入对骨生长（33.63对33.68毫米）、骨强度（破坏载荷降低19.7%）、骨结构（骨体积分数降低58%）和峰值骨量积累（骨密度降低29%）有不利影响，这是由于钙代谢中隐含的激素紊乱所致。相比之下，观察到了新颖且令人惊讶的结果，即高于适量钙的摄入导致峰值骨强度提高（刚度从106对184N/mm，破坏载荷从61对89N）和骨材料特性改善（组织硬度从467对514mPa）但这些影响并未伴随骨量、大小、微观结构或骨转换的变化。还评估了激素因子、胰岛素样生长因子-I（IGF-I）和骨建模。与适量钙水平相比IGF-I水平在低钙摄入组显著降低，在高钙摄入组显著升高至少在这种短期干预中未观察到高钙对骨建模有不利影响（通过组织形态计量学和骨标志物评估）。总之，低钙组破坏载荷的降低可通过骨几何形状和骨量参数的变化来解释。因此力学性能的改善可通过纳米压痕显示的骨组织内在质量的改善来解释。这些结果表明补充钙可能有利于达到峰值骨强度，并且在设定充足矿物质摄入的饮食水平以支持最佳峰值骨量获取时应考虑与骨量和强度相关的多个因素。
