Lazenby Richard A, Angus Sarah, Cooper David M L, Hallgrímsson Benedikt
Anthropology Program, University of Northern British Columbia, Prince George, BC, Canada.
J Anat. 2008 Dec;213(6):698-705. doi: 10.1111/j.1469-7580.2008.00991.x.
Variation in trabecular microarchitecture is widely accepted as being regulated by both functional (mechanical loading) and genetic parameters, although the relative influence of each is unclear. Studies reporting inter-site differences in trabecular morphology (volume, number and structure) reveal a complex interaction at the gene-environment interface. We report inter- and intra-site variation in trabecular anatomy using a novel model of contralateral (left vs right) and ipsilateral (head vs base) comparisons for the human second metacarpal in a sample of n = 29 historically known 19th century EuroCanadians. Measures of bone volume fraction, structure model index, connectivity, trabecular number, spacing and thickness as well as degree of anisotropy were obtained from 5-mm volumes of interest using three-dimensional microcomputed tomography. We hypothesized that: (i) the more diverse loading environment of metacarpal heads should produce a more robust trabecular architecture than corresponding bases within sides and (ii) the ipsilateral differences between epiphyses will be larger on the right side than on the left side, as a function of handedness. Analysis of covariance (Side x Epiphysis) with Age as covariate revealed a clear dichotomy between labile and constrained architectures within and among anatomical sites. The predicted variation in loading was accommodated by changes in trabecular volume, whereas trabecular structure did not vary significantly by side or by epiphysis within sides. Age was a significant covariate only for females. We conclude that environmental and genetic regulation of bone adaptation may act through distinct pathways and local anatomies to ensure an integrated lattice of sufficient mass to meet normal functional demands.
小梁微结构的变异被广泛认为受功能（机械负荷）和遗传参数两者调节，尽管各自的相对影响尚不清楚。报告小梁形态（体积、数量和结构）部位间差异的研究揭示了基因 - 环境界面的复杂相互作用。我们使用一种新颖的对侧（左对右）和同侧（头对头与基部对基部）比较模型，对29例历史上已知的19世纪欧洲裔加拿大人样本的人类第二掌骨进行小梁解剖结构的部位间和部位内变异研究。使用三维显微计算机断层扫描从5毫米感兴趣体积中获取骨体积分数、结构模型指数、连通性、小梁数量、间距和厚度以及各向异性程度的测量值。我们假设：（i）掌骨头更多样化的负荷环境应比同一侧相应的基部产生更坚固的小梁结构；（ii）作为利手的函数，骨骺之间的同侧差异在右侧将比左侧更大。以年龄作为协变量的协方差分析（侧别×骨骺）揭示了解剖部位内和部位间不稳定和受限结构之间的明显二分法。小梁体积的变化适应了预测的负荷变化，而小梁结构在侧别之间或同一侧的骨骺之间没有显著差异。年龄仅对女性是一个显著的协变量。我们得出结论，骨骼适应性的环境和遗传调节可能通过不同途径和局部解剖结构起作用，以确保形成具有足够质量的综合晶格以满足正常功能需求。
