Kinetics of Thermal Injury in Cells

Abstract

HeLa cells, suspended in solution, were subjected to well-defined temperature protocols on a microscope stage specifically designed for this purpose. Simultaneously, the appearance of the first irreversible morphological change in the cells was monitored and used as an indicator of damage. For constant temperature protocols, an Arrhenius relationship was found between the measured damage time and the cell temperature, yielding an activation energy of 249 kJ/mole (59.5 kcal/mole) and a frequency factor of 9.09 × 1036 s−1 . On the basis of this result and of Henriques’ damage integral concept [1], working relationships have been derived to express the damage time for two additional temperature protocols; viz., 1 a linearly increasing temperature, and 2 a linearly increasing temperature followed by a constant temperature. These relationships show the dependence of the damage time on the heating rate, the maximum attained temperature, the damage kinetics and the initial cell temperature.