Background: Cryopreservation is of particular importance in stem cell research and regenerative medicine as it permits long term stabilisation of biological cells. Cells retain their regenerative capacity after years of storage at cryogenic temperatures. However, elevation of temperature may occur due to variety of reasons, for example in the event of equipment malfunction or during delays in transportation. To date, a limited amount research has been carried out to examine the effects of temperature elevation on stem cell survival during cryopreservation.
Methods: Mesenchymal Stem Cells (MSCs) obtained from 8-12 week Sprague Dawley male rats were cryopreserved according to the standard procedures. Under experimental conditions, cryopreserved specimens were exposed to elevated temperatures ranging from -20 C to 37 C and cellular membrane integrity assessed via trypan-blue exclusion at various time points.
Results: An approximating model of multiple regression was fitted to the experimental data and optimisation of model parameters was carried out. This model provides an approximation of cell viability in response to elevated temperature conditions.
Discussion: The results demonstrate that elevation of temperature has a dramatic effect, even over short periods of time, on the viability of cryopreserved specimens. The model presented here could be used to predict the damage suffered by a specimen due to exposure to elevated temperature over a defined period of time.