Upregulation of aggrecan and type II collagen mRNA expression in bovine chondrocytes by the application of hydrostatic pressure.

The aim of this study was to investigate the effect of hydrostatic pressure on the expression of messenger ribonucleic acid (mRNA) for specific extracellular matrix proteins in chondrocytes. Chondrocytes obtained from bovine metatarsophalangeal joints were embedded in cylindrical 2% agarose gels. A novel experimental system was used to apply 5 MPa of static hydrostatic pressure to these chondrocytes for 4 hours. The application of hydrostatic pressure caused a significant increase in the level of aggrecan mRNA by almost four fold (p<0.01) as well as a 50% increase in the level of type II collagen mRNA (p<0.05). However, there was no significant change in the level of TIMP-1 mRNA. It was suggested that the application of hydrostatic pressure, in the absence of cell deformation, can bring about changes in the matrix components which may play an important role in the homeostasis and mechanical properties of articular cartilage.