The Effects of Hypothermic Storage on Chondrocyte Survival and Apoptosis in Human Articular Cartilage

As a result of recent advances in diagnostic technology and an increased awareness among clinicians, osteochondral injury is being detected more frequently. Because there is little or no regenerative capacity in adult articular cartilage (AC), there is a need to preserve and store AC for the repair of joint surfaces. Chondrocytes embedded within extracellular matrix must remain viable during storage for successful tissue transplantation. This study was designed to contribute toward establishing a timeline and suitable conditions for storing human AC, compare human chondrocyte survival with bovine results, and finally, distinguish apoptosis from necrosis in human AC after hypothermic storage. We hypothesized that the presence of reactive oxygen species, that increase at hypothermic temperatures, could induce apoptosis and lead to the degradation of banked tissue. Osteochondral dowels were drilled from eight cadaveric femoral condyles. At least five dowels were obtained from each joint. The first was used for initial viability/annexin V assays, the others were stored in either phosphate-buffered saline (PBS) or Biowhitaker X-VIVO-10 (BioWhittaker, East Rutherford, NJ) for 4 and 6 weeks. After storage, final viability, annexin V, and TUNEL assays were performed. Chondrocytes remain viable (68%) for up to 1 month and apoptosis is minimal when human AC is stored in a biopreservative under hypothermic conditions (4 C). Storage times are now adequate for AC banking and further research is likely to significantly improve current techniques. An osteochondral tissue bank would provide a reliable source of AC for repairing joint surfaces in athletic, young patients who are not suitable candidates for total joint replacements.