Démarteau O, Pillet L, Inaebnit A, Borens O, Quinn T M
Cartilage Biomechanics Group, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland.
Osteoarthritis Cartilage. 2006 Jun;14(6):589-96. doi: 10.1016/j.joca.2005.12.011. Epub 2006 Feb 14.
In vitro mechanical injury of articular cartilage is useful to identify events associated with development of post-traumatic osteoarthritis (OA). To date, many in vitro injury models have used animal cartilage despite the greater clinical relevance of human cartilage. We aimed to characterize a new in vitro injury model using elderly human femoral head cartilage and compare its behavior to that of an existing model with adult bovine humeral head cartilage.
Mechanical properties of human and bovine cartilage disks were characterized by elastic modulus and hydraulic permeability in radially confined axial compression, and by Young's modulus, Poisson's ratio, and direction-dependent radial strain in unconfined compression. Biochemical composition was assessed in terms of tissue water, solid, and glycosaminoglycan (GAG) contents. Responses to mechanical injury were assessed by observation of macroscopic superficial tissue cracks and histological measurements of cell viability following single injurious ramp loads at 7 or 70%/s strain rate to 3 or 14 MPa peak stress.
Confined compression moduli and Young's moduli were greater in elderly human femoral cartilage vs adult bovine humeral cartilage whereas hydraulic permeability was less. Radial deformations of axially compressed explant disks were more anisotropic (direction-dependent) for the human cartilage. In both cartilage sources, tissue cracking and associated cell death during injurious loading was common for 14 MPa peak stress at both strain rates.
Despite differences in mechanical properties, acute damage induced by injurious loading was similar in both elderly human femoral cartilage and adult bovine humeral cartilage, supporting the clinical relevance of animal-based cartilage injury models. However, inherent structural differences such as cell density may influence subsequent cell-mediated responses to injurious loading and affect the development of OA.
关节软骨的体外机械损伤有助于识别与创伤后骨关节炎（OA）发展相关的事件。迄今为止，尽管人类软骨具有更大的临床相关性，但许多体外损伤模型仍使用动物软骨。我们旨在表征一种使用老年人类股骨头软骨的新型体外损伤模型，并将其行为与现有的成年牛肱骨头软骨模型进行比较。
通过径向受限轴向压缩中的弹性模量和水力渗透率，以及无约束压缩中的杨氏模量、泊松比和方向依赖性径向应变来表征人类和牛软骨盘的力学性能。根据组织水、固体和糖胺聚糖（GAG）含量评估生化组成。通过观察宏观表面组织裂缝以及在7或70%/秒应变率下施加单次损伤斜坡载荷至3或14兆帕峰值应力后细胞活力的组织学测量来评估对机械损伤的反应。
老年人类股骨软骨的受限压缩模量和杨氏模量高于成年牛肱骨头软骨，而水力渗透率较低。对于人类软骨，轴向压缩外植体盘的径向变形更具各向异性（方向依赖性）。在两种软骨来源中，在两种应变率下，14兆帕峰值应力时，损伤加载过程中的组织开裂和相关细胞死亡都很常见。
尽管力学性能存在差异，但老年人类股骨软骨和成年牛肱骨头软骨在损伤加载引起的急性损伤方面相似，这支持了基于动物的软骨损伤模型的临床相关性。然而，诸如细胞密度等内在结构差异可能会影响随后细胞介导的对损伤加载的反应，并影响OA的发展。
