Sharma Blanka, Williams Christopher G, Kim Tae Kyun, Sun Dongning, Malik Athar, Khan Mehnaz, Leong Kam, Elisseeff Jennifer H
Department of Biomedical Engineering, Johns Hopkins University School of Engineering, Baltimore, Maryland 21218, USA.
Tissue Eng. 2007 Feb;13(2):405-14. doi: 10.1089/ten.2006.0068.
Cartilage tissue engineering strategies generally result in homogeneous tissue structures with little resemblance to the native zonal organization of articular cartilage. The objective of this study was to use bilayered photopolymerized hydrogels to organize zone-specific chondrocytes in a stratified framework and study the effects of this three-dimensional coculture system on the properties of the engineered tissue. Superficial and deep zone chondrocytes from bovine articular cartilage were photoencapsulated in separate hydrogels as well as in adjacent layers of a bilayered hydrogel. Histology, mechanical testing, and biochemical analysis was performed after culturing in vitro. To evaluate the influence of coculture on tissue properties, the layers were separated and compared to constructs containing only superficial or deep cells. In the bilayered constructs, deep cells produced more collagen and proteoglycan than superficial cells, resulting in cartilage tissue with stratified, heterogeneous properties. Deep cells cocultured with superficial cells in the bilayered system demonstrated reduced proliferation and increased matrix synthesis compared to deep cells cultured alone. The bilayered constructs demonstrated greater shear and compressive strength than homogenous cell constructs. This study demonstrated that interactions between zone-specific chondrocytes affect the biological and mechanical properties of engineered cartilage. Strategies aimed to structurally organize zone-specific cells and encourage heterotypic cell interactions may contribute to improved functional properties of engineered cartilage.
软骨组织工程策略通常会产生结构均匀的组织结构，与关节软骨的天然分层组织几乎没有相似之处。本研究的目的是使用双层光聚合水凝胶在分层框架中组织特定区域的软骨细胞，并研究这种三维共培养系统对工程组织特性的影响。将来自牛关节软骨的表层和深层软骨细胞分别光包封在水凝胶中以及双层水凝胶的相邻层中。体外培养后进行组织学、力学测试和生化分析。为了评估共培养对组织特性的影响，将各层分离并与仅含有表层或深层细胞的构建体进行比较。在双层构建体中，深层细胞比表层细胞产生更多的胶原蛋白和蛋白聚糖，从而形成具有分层、异质性特性的软骨组织。与单独培养的深层细胞相比，在双层系统中与表层细胞共培养的深层细胞增殖减少，基质合成增加。双层构建体表现出比同质细胞构建体更大的剪切强度和抗压强度。本研究表明，特定区域软骨细胞之间的相互作用会影响工程软骨的生物学和力学特性。旨在在结构上组织特定区域细胞并促进异型细胞相互作用的策略可能有助于改善工程软骨的功能特性。
