In Vitro Calcification of Immature Bovine Articular Cartilage: Formation of a Functional Zone of Calcified Cartilage
In Vitro Calcification of Immature Bovine Articular Cartilage: Formation of a Functional Zone of Calcified Cartilage
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DOI：
10.1177/1947603510369552
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发表时间：
2010-10-01
期刊：
影响因子：
2.8
通讯作者：
Sah, Robert L.
中科院分区：
文献类型：
--
作者：
Hwang, Jennifer;Kyubwa, Espoir M.;Sah, Robert L.
简介：钙化软骨区（ZCC）通过中间硬度层将关节软骨（AC）锚定到软骨下骨。软骨钙化的调节和功能后果可能随着距关节面的深度而变化。本研究的假设是，未成熟AC的体外钙化选择性地发生在深部区域，并且与刚度的局部增加相关。研究方法：将来自小牛的AC和生长板软骨（GPC）在DMEM、1%胎牛血清、100 μ g/mL抗坏血酸盐和+/-10 mM β-甘油磷酸盐（β GP）中孵育长达3周。为了评估细胞活力和β GP的时间过程和影响，通过组织学、压痕和Ca-45（++）摄取分析AC和GPC的全深度条。为了评估组织区的影响，将从AC的表面和深层以及从GPC的储备和肥大区收获的盘独立地孵育，并通过压缩和45 Ca ++摄取和生化组分进行分析。结果：20%的未成熟AC在3周内钙化，钙化依赖于细胞活力和β GP。在AC中，矿物连续地沉积在细胞周围，而在GPC中，矿物仅沉积在细胞柱之间。AC的深部区域在β GP诱导的钙化后表现出0.53 MPa的压缩模量，类似于比不含β GP的AC孵育的刚性高4倍。结论：软骨外植体表现出固有的区域特异性钙化过程，导致与软骨钙化相关的刚度增加。这样的性质可用于工程化仿生ZCC组织以将软骨组织整合到骨，从而形成机械功能性骨软骨单元。
Introduction: The zone of calcified cartilage (ZCC) anchors articular cartilage (AC) to subchondral bone through a layer of intermediate stiffness. The regulation and functional consequences of cartilage calcification may vary with depth from the articular surface. The hypothesis of this study was that the in vitro calcification of immature AC occurs selectively in the deep region and is associated with a local increase in stiffness. Methods: AC and growth plate cartilage (GPC) from calves were incubated in DMEM, 1% fetal bovine serum, 100 mu g/mL ascorbate, and +/- 10 mM beta-glycerophosphate (beta GP) for up to 3 weeks. To assess the time course and effects of cell viability and beta GP, full-depth strips of AC and GPC were analyzed by histology, indentation, and Ca-45(++) uptake. To assess the effect of tissue zone, disks harvested from surface and deep zone AC and from reserve and hypertrophic zone of GPC were incubated independently and analyzed by compression and for 45Ca++ uptake and biochemical components. Results: The deep similar to 20% of immature AC calcified within 3 weeks, with calcification dependent on cell viability and beta GP. Mineral was deposited continuously around cells in AC but only between cell columns in GPC. The deep zone of AC exhibited a compressive modulus of 0.53 MPa after beta GP-induced calcification, similar to 4-fold stiffer than AC incubated without beta GP. Conclusions: Cartilage explants exhibit inherent zone-specific calcification processes, resulting in an increase in stiffness associated with cartilage calcification. Such properties may be useful for engineering a biomimetic ZCC tissue to integrate cartilaginous tissue to bone, thereby forming a mechanically functional osteochondral unit.