Article
Surface Motion as a New Loading Concept to Induce Superficial Zone Protein / Lubricin Expression in Tissue Engineered Cartilage
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Published: | November 11, 2003 |
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Outline
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Introduction
Dynamic loading is a valuable tool for in vitro conditioning of tissue engineered cartilage grafts. Surface motion may provide additional stimulation. In the present study the effect of cyclic compression and surface motion on gene expression of chondrocytes seeded onto polymer scaffolds was investigated, with specific emphasis on SZP/lubricin, which is thought to play a key role in maintaining a functional articular surface and joint lubrication.
Methods
Cylindrical (8mmx4mm) polyurethane scaffolds were seeded with bovine articular chondrocytes and subjected to cyclic compression and/or surface motion, which was accomplished by rotation of a ceramic hip ball over the construct surface. After loading (2x1h/day for 3 days), the mRNA expression of SZP/lubricin was analysed by real-time PCR and compared to mRNA levels of free swelling constructs. SZP/lubricin immunoreactivity of culture media was determined by western blot analysis.
Results
Dynamic compression had no effect on SZP/lubricin gene expression; surface motion significantly up-regulated its expression, independent of additional compressive loading. SZP/lubricin was detected only in media of constructs exposed to surface motion.
Discussion
The results of this study indicate that reciprocating sliding is a potent modulator of SZP/lubricin expression. Applied surface motion may therefore be a useful tool for growing cartilage-like constructs with a functional surface.