The role of hydrogel structure and dynamic loading on chondrocyte gene expression and matrix formation
The role of hydrogel structure and dynamic loading on chondrocyte gene expression and matrix formation
复制标题
DOI：
10.1016/j.jbiomech.2008.02.034
复制
发表时间：
2008-01-01
影响因子：
2.4
通讯作者：
Bryant, S. J.
中科院分区：
文献类型：
--
作者：
Nicodemus, G. D.;Bryant, S. J.
交联聚乙二醇（PEG）水凝胶是软骨组织工程的有吸引力的支架，因为它们能够模拟天然软骨的水环境和机械性能。在本研究中，改变水凝胶交联密度以研究凝胶结构和施加动态载荷（连续，1Hz，15%振幅应变）对软骨细胞基因表达的影响，其类似于1周培养。使用实时RT-PCR定量胶原蛋白II和聚集蛋白聚糖（主要软骨细胞外基质（ECM）组分）以及胶原蛋白I（软骨细胞去分化的指标）的基因表达。当软骨细胞包封在具有低或高交联的PEG凝胶中时，与胶原蛋白I表达相比的高胶原蛋白II表达（分别为1000或100，000：1）表明保留了天然软骨细胞表型。在没有加载的情况下，胶原II和聚集蛋白聚糖的相对基因表达显著更高（例如，2-与具有较高交联的凝胶相比，在低交联的凝胶中，第7天分别为4倍和4倍）。然而，动态加载显示在两种交联系统中对ECM基因表达的影响很小。为了更好地了解细胞环境，使用原位免疫荧光技术和标准组织学定性评估了ECM的产生。早在包封后第3天就观察到细胞周基质（PCM），形成的程度取决于凝胶交联。这些结果表明，PCM可以保护细胞免受所施加的负载的影响。这项研究表明，凝胶结构对软骨细胞基因表达有深远的影响，而动态负荷在早期培养时间的影响要小得多。(c)2008爱思唯尔有限公司保留所有权利。
Crosslinked poly(ethylene glycol) (PEG) hydrogels are attractive scaffolds for cartilage tissue engineering because of their ability to mimic the aqueous environment and mechanical properties of native cartilage. In this study, hydrogel crosslinking density was varied to study the influence of gel structure and the application of dynamic loading (continuous, 1 Hz, 15% amplitude strain) on chondrocyte gene expression over similar to 1 week culture. Gene expression was quantified using real-time RT-PCR for collagen II and aggrecan, the major cartilage extracellular matrix (ECM) components, and collagen I, an indicator of chondrocyte de-differentiation. When chondrocytes were encapsulated in PEG gels with low or high crosslinking, a high collagen II expression compared to collagen I expression (1000 or 100,000: 1, respectively) indicated the native chondrocyte phenotype was retained. In the absence of loading, relative gene expression for collagen II and aggrecan was significantly higher (e.g., 2-fold and 4-fold, respectively, day 7) in the low crosslinked gels compared to gels with higher crosslinking. Dynamic loading, however, showed little effect on ECM gene expression in both crosslinked systems. To better understand the cellular environment, ECM production was qualitatively assessed using an in situ immunofluorescent technique and standard histology. A pericellular matrix (PCM) was observed as early as day 3 post-encapsulation and the degree of formation was dependent on gel crosslinking. These results suggest the PCM may protect the cells from sensing the applied loads. This study demonstrates that gel structure has a profound effect on chondrocyte gene expression, while dynamic loading has much less of an effect at early culture times. (c) 2008 Elsevier Ltd. All rights reserved.