Cryoprotectant permeation through human articular cartilage

Objective: The cryopreservation of intact articular cartilage is constrained by minimal chondrocyte survival. It was the aim of the present study to gain an insight into the permeation kinetics of cryoprotectants through cartilage. This knowledge is essential for achieving adequate tissue permeation prior to cooling. Design: The diffusion coefficients and penetration rates through human articular cartilage of dimethyl sulfoxide (Me2SO) and glycerol at different temperatures (4degreesC, 17degreesC, 27degreesC and 37degreesC) and at two concentrations [10% (v/v) and absolute state] were measured using diffusion nuclear magnetic imaging. Deuterated water (D2O) was used as a control substance. Results: Glycerol penetrated faster than Me2SO at all temperatures and at rates that were comparable to those for D2O. The penetration rate of each agent increased with increasing temperature. The diffusion coefficients for glycerol and Me2SO increased with increasing temperature and decreased at the higher concentration, but the differences between each agent were not significant. Conclusions: The classical cryopreservation protocols expose cartilage samples to Me2SO at a too low temperature and/or for an insufficient time period for optimal cell survival. When considering the penetration rate, glycerol appears to be a more efficient cryoprotective agent than Me2SO. The present study demonstrates the power of nuclear magnetic resonance technology to elucidate key physiological factors in cryobiology. (C) 2004 OsteoArthritis Research Society International. Published by Elsevier Ltd. All rights reserved.