Supercooling Storage for the Transplantable Sources From the Rat and the Rabbit: A Preliminary Report

It is necessary to store the transplantable sources for a certain period during the variety of manipulation processing steps. The method used to preserve (depending on conditions of solvent, temperature, periods, density, and physical impulse, etc.) can affect the safety and efficacy of the samples. Supercooling refers to a phenomenon of lowering the temperature below its freezing point without freezing. We investigated the possibility of supercooling for the preservation of cells and organs according to the limited conditions.

The viability of mesenchymal stem cells (MSCs) derived from the intra-abdominal fat of the New Zealand white rabbit were observed, and the neonatal rat kidneys were maintained in histidine-tryptophan-ketoglutarate solution and stored at various temperatures for 48 hours. The supercooling refrigerator was used for -2 °C and -5 °C in controlled preservation conditions. We observed and compared histopathological changes of samples at each temperature condition.

As time passed, the number of rabbit MSCs decreased in each group with storage temperature. At room temperature, the number of viable MSCs decreased rapidly, but the number of MSCs tended to decrease slowly in the cooling and supercooling groups. The rat kidneys preserved on supercooling temperature at -2 °C tended to have the least damage on the cortex and medulla parenchyma.

The difference in damage of transplantable sources by storage temperature conditions is the evidence that effectiveness may depend on the storage method. It is necessary to determine further optimal supercooling temperature of the preservation methods with various cells, tissues, and organs in the future.