Wong M, Wuethrich P, Buschmann M D, Eggli P, Hunziker E
M.E. Mueller Institute for Biomechanics, University of Bern, Switzerland.
J Orthop Res. 1997 Mar;15(2):189-96. doi: 10.1002/jor.1100150206.
In this study, we investigated the depth-dependent metabolic and structural responses of adult articular cartilage to large-strain, static, unconfined compression. Changes in cell biosynthetic activity and several morphometry-based structural parameters (cell density, cell volume fraction, cell surface-area density, mean cell surface area, and mean cell volume) were measured at eight sites representing different depth-zones between the articular surface and the cartilage/bone border. In addition, local axial strain in the superficial, transitional, upper radial, and lower radial zones was estimated on the basis of the change in cell density values. Static compression of articular cartilage revealed a highly heterogeneous deformation profile through the depth of the sample as well as zone-specific changes in biosynthetic activity, as reflected by incorporation of [3H]proline. The axial strains in the top layers were greater than the applied surface-to-surface strain, whereas axial strains adjacent to the cartilage/bone border were significantly less than the applied strain. Zonal changes in cell density and axial strain that occurred during static compression correlated well with alterations in metabolic activity. These coordinated changes between cell biosynthesis and cartilage structure suggest that zone-specific variations in mechanical stimuli could be responsible for spatially varied patterns of cartilage metabolic activity under load.
在本研究中，我们调查了成年关节软骨对大应变、静态、无侧限压缩的深度依赖性代谢和结构反应。在代表关节表面与软骨/骨边界之间不同深度区域的八个位点，测量了细胞生物合成活性的变化以及几个基于形态测量学的结构参数（细胞密度、细胞体积分数、细胞表面积密度、平均细胞表面积和平均细胞体积）。此外，根据细胞密度值的变化，估算了表层、过渡层、上辐射层和下辐射层的局部轴向应变。关节软骨的静态压缩显示，整个样本深度的变形分布高度不均匀，生物合成活性也呈现区域特异性变化，这通过[3H]脯氨酸的掺入得以体现。顶层的轴向应变大于施加的表面对表面应变，而与软骨/骨边界相邻处的轴向应变明显小于施加的应变。静态压缩过程中发生的细胞密度和轴向应变的区域变化与代谢活性的改变密切相关。细胞生物合成与软骨结构之间的这些协同变化表明，机械刺激的区域特异性变化可能是负载下软骨代谢活性空间变化模式的原因。
