Continuous passive motion applied to whole joints stimulates chondrocyte biosynthesis of PRG4

G.E. Nugent-Derfus, T. Takara, J.K. O'Neill, S.B. Cahill, S. Görtz, T. Pong, H. Inoue, N.M. Aneloski, W.W. Wang, K.I. Vega et al.

The objective of this study was to determine the topographical variation in intrinsic cartilage proteoglycan 4 (PRG4) secretion and to apply a continuous passive motion (CPM) device to whole joints in bioreactors and assess effects of CPM on PRG4 biosynthesis.  A bioreactor was developed to apply CPM to bovine stifle joints in vitro. Effects of 24 h of CPM on PRG4 biosynthesis were determined.  The results showed PRG4 secretion rate varied markedly over the joint surface. Rehabilitative joint motion applied in the form of CPM regulated PRG4 biosynthesis, in a manner dependent on the duty cycle of cartilage sliding against opposing tissues. Specifically, in certain regions of the femoral condyle that were continuously or intermittently sliding against meniscus and tibial cartilage during CPM, chondrocyte PRG4 synthesis was higher with CPM than without.The authors concludet that rehabilitative joint motion, applied in the form of CPM, stimulates chondrocyte PRG4 metabolism. The stimulation of PRG4 synthesis is one mechanism by which CPM may benefit cartilage and joint health in post-operative rehabilitation.

Osteoarthritis and Cartilage, Volume 15, Issue 5, May 2007, Pages 566-574

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