Water-Transport and Intracellular Ice Formation Of Porcine Adipose-Derived Stem Cells During Freezing

BACKGROUND: Water transport and intracellular ice formation are important processes that relate to cryoinjury of cells upon freezing. To date, no study is reported on the characteristics of water transport and intracellular ice formation in porcine adipose–derived stem cells (pADSC). OBJECTIVE: To study water transport and intracellular ice formation upon freezing of pADSCs at different cooling rates. MATERIALS AND METHODS: The pADSCs were isolated using collagenase digestion from a subcutaneous adipose tissue of a 28–day–old Landrace pig. Freeze experiments were performed in a gas tight chamber of cryomicroscopy stage at different cooling rates between 40°C and 150°C. RESULTS: Water permeability coefficient Lpg and the activation energy E_LP decrease with increasing cooling rates for pADSCs. The probability of intracellular ice formation increases with increasing cooling rates, being 0.35, 0.4 and 0.5 for cooling rates at 20, 30 and 60 °C/min respectively. CONCLUSION: Based on the characteristics of water transport and intracellular ice formation in pADSCs, slow freezing is perhaps more suitable for pADSC cryopreservation.