Freezing characteristics of isolated pig and human hepatocytes

The cellular response of isolated hepatocytes from pigs, humans, and human hepatoblastoma cells to freezing was characterized using cryomicroscopy and analyzed using a thermodynamic model for water transport and Intracellular Ice Formation (IIF). The value for the reference permeability, L(pg), was found to be 5.8(10)^-13, 1.62(10)^-13, and 2.7(10)^-14 m/Ns for pig, human, and Hep G2/C3A cells, respectively. The activation energy, E(lp), was found to be 480 kJ/mol for pig hepatocytes, 216 kJ/mol for human, and 121 kJ/mol for Hep G2/C3A cells. The average temperature at which IIF (T(IIF)/(avg)) occurs was calculated to be -7.24 ± 2.3°C for pig hepatocytes, -8.5 ± 2.6°C for human hepatocytes, and -9.6 ± 4.5°C for Hep G2/C3A cells. These results indicate that the freezing characteristics of pig and human cells are distinct and that the specific freezing characteristics need to be understood for the development of appropriate freezing protocols.