Contributions of intermittent cyclic compression to proteoglycans synthesis and mechanical properties of knee articular cartilaginous tissue formed in vitro

The formation of cartilaginous tissue in vitro is a promising alternative to repair damaged articular cartilage. In this study, we investigated whether application of intermittent cyclic compression during knee articular cartilage formation would improve the tissue quality. Intermittent cyclic compression (0.08Mpa) was applied to the chondrocyte/agarose constructs using Flexercell compressive system at 0.2Hz for duration 2h, followed 22 recovery per day; such action was repeated for 7d, 14d or 21days respectively. proteoglycan synthesis and mechanical properties were measured after loading. Our results showed that long term intermittent cyclic compression (21days) at low frequency significantly stimulated proteoglycan synthesis and improved the mechanical properties of the knee articular cartilaginous tissue formed in vitro, and there was a correlation between the proteoglycan levels and mechanical properties.