A new application of Gompertz function in photohemolysis: the effect of temperature on red blood cell hemolysis photosensitized by protoporphyrin IX

Photosensitization by protoporphyrin IX (PpIX) is accelerated at different irradiation temperatures, different dark incubation temperatures (Tin,) and different irradiation times. The applicability of Gompertz function to the fractional photohemolysis ratio, a and the rate of fractional photohemolysis, b is found to be the most appropriate model to fit the experimental data with minimum parameters and minimum errors. The reduction in Gompertz parameters, the fractional ratio values of a, and increase in the fractional rate values b, for 20 mu M PpIX irradiated with black light at low irradiation temperature 5 degrees C and higher T-inc 37 degrees C was noticed. The parameter a has higher values at lower irradiation time and lower irradiation temperatures which indicates a longer photohemolysis process and longer t(50). Values of the parameter b were found to be strongly temperature-dependent, and always increase with increasing irradiation time and Tinc with lower values at lower irradiation time and lower Tinc. There are no significant changes in the lysis of RBCs process at irradiation temperatures equal to or higher than 35 degrees C. Similarly, no significant change on t(50) at higher irradiation time at T-inc 24 and 37 degrees C. In conclusion, Gompertz analysis technique adapts to study the photohemolysis process at different conditions as a best-fit model.