Perfusion Increases Cell Content and Matrix Synthesis in Chondrocyte Three-Dimensional Cultures

This work examines the effect of perfusion on the cell content and sulfated glycosaminoglycan synthesis of ovine articular chondrocytes cultured on polyglycolic acid (PGA) scaffolds. Ovine chondrocytes were seeded onto the scaffolds and cultured for up to 9 days. During this time the cells were subjected to perfusion at velocities of up to 170 μm/s. The samples were radiolabeled with ³⁵SO₄ to quantify the overall synthesis of sulfated glycosaminoglycans (S-GAGs) and the retention of S-GAGs in the construct. The constructs were also analyzed for DNA as a measure of cellular content. Constructs subjected to perfusion during culture had significantly higher DNA contents than those cultured statically. Matrix metabolism was also modulated by perfusion, with this modulation depending on culture duration. Nine days of continuous perfusion increased S-GAG synthesis and deposition by approximately 40% when compared with static controls. However, perfusion at early time points (during the initial 3-day culture period) suppressed the synthesis and retention of S-GAGs when compared with controls. This work demonstrates the effects of perfusion on cartilage growth in vitro, illustrating the use of perfusion to modulate the growth of tissue-engineered cartilage constructs, and potentially enhance tissue growth in vitro.