Temporal regulation of chondrocyte metabolism in agarose constructs subjected to dynamic compression

The temporal response of chondrocyte metabolism in agarose constructs subjected to different dynamic compression regimes was investigated. The current study explored the effects of continuous or intermittent compression using various duty cycles of dynamic compressive loading, over a 48 h culture period. For the continuous compression experiments, duty cycles ranged from 5400 to 172,800 and intermittent compression delivered a total of 86,400 cycles. Large numbers of duty cycles significantly stimulated proteoglycan synthesis with maximal levels obtained for constructs subjected to 12 h of intermittent compression. The shortest duration of intermittent compression suggested that further cycles are inhibitory for cell proliferation. Nitrite release was independent of the length or type of compressive regime applied. The uncoupled nature of the metabolic response determined in this study suggests that mechanical conditioning regimes may be fine tuned to selectively stimulate key metabolic parameters of relevance to cartilage tissue engineering. (C) 2003 Elsevier Inc. All rights reserved.