The effect of cooling on cellular changes during the freeze-thaw cycle

Progressive changes to MRC-5 and CHA cells during the cooling process were measured by thawing samples of cells in 10% DMSO from various points in the cooling phase between +20 ° and ?196 °C. The results showed that the period of phase transition was not the part of the cooling process in which cells were most susceptible to freeze-thaw damage. Indications were that most cell damage, as measured by the release of radiochromate, occurred between ?30 ° and ?80 °C. The possibility that cell survival from freeze-thaw cycles could be improved by the use of different cooling rates at different stages of the cooling process was investigated.