Reproduction Differentially Affects Trabecular Bone Depending on Its Mechanical Versus Metabolic Role
Reproduction Differentially Affects Trabecular Bone Depending on Its Mechanical Versus Metabolic Role
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DOI：
10.1115/1.4038110
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发表时间：
2017-11-01
影响因子：
1.7
通讯作者：
Liu, X. Sherry
中科院分区：
文献类型：
--
作者：
de Bakker, Chantal M. J.;Tseng, Wei-Ju;Liu, X. Sherry
在怀孕和哺乳期间，母体骨骼为胎儿/婴儿的生长提供钙，导致大量骨质流失，在断奶后部分恢复。然而，骨质丢失的数量和断奶后恢复的程度在不同的骨骼部位是高度不同的，尽管某些部位的骨骼结构持续改变，生育史并不会增加绝经后骨折的风险。为了解释这一现象，我们假设骨小梁部位的生殖骨丢失/恢复程度可能取决于骨小梁室参与骨承重功能的程度。使用大鼠模型，我们量化了小梁所承载的负荷比例，以及两个不同骨骼部位（胫骨和腰椎）的生殖骨丢失和恢复的程度。这两个部位在怀孕和哺乳期间都有明显的骨质流失，在断奶后部分恢复。然而，退化的程度和断奶后小梁承重能力的恢复有很大的不同。胫骨小梁骨承受的总载荷比例较低，在繁殖过程中发生了剧烈的、不可逆的微结构退化。与此同时，椎小梁骨承受了更大的负荷，微结构恶化最小，断奶后恢复其全部承载能力。由于怀孕和哺乳是生理过程，不同骨骼部位对这些自然事件的不同反应可能有助于阐明小梁骨的结构与代谢功能的程度。
During pregnancy and lactation, the maternal skeleton provides calcium for fetal/infant growth, resulting in substantial bone loss, which partially recovers after weaning. However, the amount of bone that is lost and the extent of post-weaning recovery are highly variable among different skeletal sites, and, despite persistent alterations in bone structure at some locations, reproductive history does not increase postmenopausal fracture risk. To explain this phenomenon, we hypothesized that the degree of reproductive bone loss/recovery at trabecular sites may vary depending on the extent to which the trabecular compartment is involved in the bone's load-bearing function. Using a rat model, we quantified the proportion of the load carried by the trabeculae, as well as the extent of reproductive bone loss and recovery, at two distinct skeletal sites: the tibia and lumbar vertebra. Both sites underwent significant bone loss during pregnancy and lactation, which was partially recovered post-weaning. However, the extent of the deterioration and the resumption of trabecular load-bearing capacity after weaning varied substantially. Tibial trabecular bone, which bore a low proportion of the total applied load, underwent dramatic and irreversible microstructural deterioration during reproduction. Meanwhile, vertebral trabecular bone bore a greater fraction of the load, underwent minimal deterioration in microarchitecture, and resumed its full load-bearing capacity after weaning. Because pregnancy and lactation are physiological processes, the distinctive responses to these natural events among different skeletal sites may help to elucidate the extent of the trabecular bone's structural versus metabolic functions.