Isolation & cryo-preservation of human foetal articular chondrocytes

An attempt to determine the ideal temperature and duration of storage of human foetal chondrocytes yielded highly cellular preparations with no alteration in morphology or loss of viability. Initial digestion with activated papain was followed by incubation in 0.5 per cent collagenase. Trypan blue exclusion test revealed a viability count of 95-99 per cent and radioactive thymidine uptake a corresponding labelling index. On TEM no subcellular damage was evident. The isolated viable chondrocytes were further banked at varying temperatures of +4 degrees, -4 degrees, -30 degrees, -79 degrees and -196 degrees C, in Eagles MEM with 10 per cent dimethyl sulfoxide. Post storage morphology and viability of these cells, thawed after durations of 20 h, 1 wk, 1, 2, 3, 4 and 6 months, were compared with prestorage readings in an attempt to define the ideal temperature for banking. Storage in liquid nitrogen at -196 degrees C demonstrated excellent preservation even at the end of six months with minimal subcellular change. Electron microscopy and labelling index were found to be superior to Trypan blue exclusion test in assessing the stored chondrocytes for retention of their functions.