Background

Cartilage damage, which can potentially lead to osteoarthritis, is a leading cause of morbidity in the elderly population. Chondrocytes are sensitive to mechanical stimuli and their matrix-protein synthesis may be altered when chondrocytes experience a variety of in vivo loadings. Therefore, a study was conducted to evaluate the biosynthesis of isolated osteoarthritic chondrocytes which subjected to compression with varying dynamic compressive strains and loading durations.

Methods

The proximal tibial was resected as a single osteochondral unit during total knee replacement from patients (N = 10). The osteoarthritic chondrocytes were isolated from the osteochondral units, and characterised using reverse transcriptase-polymerase chain reaction. The isolated osteoarthritic chondrocytes were cultured and embedded in agarose, and then subjected to 10% and 20% uniaxial dynamic compression up to 8-days using a bioreactor. The morphological features and changes in the osteoarthritic chondrocytes upon compression were evaluated using scanning electron microscopy. Safranin O was used to detect the presence of cartilage matrix proteoglycan expression while quantitative analysis was conducted by measuring type VI collagen using an immunohistochemistry and fluorescence intensity assay.

Findings

Gene expression analysis indicated that the isolated osteoarthritic chondrocytes expressed chondrocyte-specific markers, including BGN, CD90 and HSPG-2. Moreover, the compressed osteoarthritic chondrocytes showed a more intense and broader deposition of proteoglycan and type VI collagen compared to control. The expression of type VI collagen was directly proportional to the duration of compression in which 8-days compression was significantly higher than 4-days compression. The 20% compression showed significantly higher intensity compared to 10% compression in 4- and 8-days.

Interpretation

The biosynthetic activity of human chondrocytes from osteoarthritic joints can be enhanced using selected compression regimes.

中文翻译：

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人骨关节炎软骨细胞生物合成和机械刺激的变化

背景

软骨损伤有可能导致骨关节炎，是老年人口发病的主要原因。软骨细胞对机械刺激敏感，当软骨细胞经历各种体内负荷时，其基质蛋白合成可能会改变。因此，进行了一项研究，以评估分离的骨关节炎软骨细胞的生物合成，这些软骨细胞受到不同的动态压缩应变和加载持续时间的压缩。

方法

在患者全膝关节置换期间，将胫骨近端切除为单个骨软骨单元（N  = 10）。从骨软骨单元分离出骨关节炎软骨细胞，并使用逆转录酶-聚合酶链反应进行表征。培养分离的骨关节炎软骨细胞并将其包埋在琼脂糖中，然后使用生物反应器进行10％和20％的单轴动态压缩，直至8天。使用扫描电子显微镜评估压缩后的骨关节炎软骨细胞的形态特征和变化。番红O被用于检测软骨基质蛋白聚糖表达的存在，而定量分析是通过使用免疫组织化学和荧光强度测定法测量VI型胶原进行的。

发现

基因表达分析表明，分离出的骨关节炎软骨细胞表达软骨细胞特异性标志物，包括BGN，CD90和HSPG-2。此外，与对照相比，压缩的骨关节炎软骨细胞显示出更强烈和更广泛的蛋白聚糖和VI型胶原蛋白沉积。VI型胶原蛋白的表达与压缩持续时间成正比，其中8天压缩明显高于4天压缩。与4天和8天的10％压缩相比，20％的压缩显示出明显更高的强度。

解释

使用选定的压缩方案可以增强来自骨关节炎关节的人软骨细胞的生物合成活性。