Institute of Biomedical Engineering and Department of Chemical Engineering, Ecole Polytechnique, Quebec, Canada.
Connect Tissue Res. 2010 Jun;51(3):216-23. doi: 10.3109/03008200903281683.
Primary chondrocytes cultured in agarose can escape the gel, accumulate at the interface between agarose and the culture medium, and form an outgrowing tissue. These outgrowths can appear as voluminous cartilage-like nodules that have never been previously investigated. In the present study, bovine articular chondrocytes from three age groups (fetal, young adult, aged) were seeded and cultured in agarose to test the hypothesis that hyaline-like cartilage outgrowths develop at the interface by appositional growth, in an age-dependant manner. Macroscopic appearance, cell content, cell division, cytoskeletal morphology, and extracellular matrix (ECM) composition were analyzed. Fetal chondrocytes produced a fibrous interfacial tissue while aged chondrocytes produced ECM-poor cell clusters. In contrast young adult chondrocytes produced large cartilaginous outgrowths, rich in proteoglycan and collagen II, where cells in the central region displayed a chondrocyte morphology. Cell proliferation was confined to the peripheral edge of these outgrowths, where elongated cell morphology, cell-cell contacts, and cell extensions toward the culture medium were seen. Thus these voluminous cartilaginous outgrowths formed in an appositional growth process and only for donor chondrocytes from young adult animals. This system offers an interesting ability to proliferate chondrocytes in a manner that results in a chondrocyte morphology and a cartilaginous ECM in central regions of the outgrowing tissue. It also provides an in vitro model system to study neocartilage appositional growth.
原代软骨细胞在琼脂糖中培养时可以逃脱凝胶，聚集在琼脂糖和培养基之间的界面处，并形成外生组织。这些外生组织可能表现为体积庞大的软骨样结节，这是以前从未研究过的。在本研究中，我们将来自三个年龄段（胎儿、年轻成年和老年）的牛关节软骨细胞播种并在琼脂糖中培养，以验证透明软骨样外生组织通过附加生长方式、以年龄依赖的方式在界面处发育的假设。我们分析了宏观外观、细胞含量、细胞分裂、细胞骨架形态和细胞外基质 (ECM) 组成。胎儿软骨细胞产生纤维状界面组织，而老年软骨细胞产生 ECM 贫乏的细胞簇。相比之下，年轻成年软骨细胞产生富含蛋白聚糖和胶原 II 的大软骨外生组织，其中中央区域的细胞呈现软骨细胞形态。细胞增殖仅限于这些外生组织的外周边缘，在那里可以看到伸长的细胞形态、细胞-细胞接触和细胞向培养基延伸。因此，这些体积庞大的软骨样外生组织是通过附加生长过程形成的，仅适用于来自年轻成年动物的供体软骨细胞。该系统提供了一种有趣的增殖软骨细胞的能力，其结果是在外生组织的中央区域形成软骨细胞形态和软骨 ECM。它还提供了一种体外模型系统来研究新软骨的附加生长。
