Comparison of ATP level in U937 cells in vitro using two different photosensitizers in photodynamic therapy

Abstract

The effect of PDT on ATP level in the Leukemic monocyte lymphoma cell line (U937) was studied using two different photosensitizers, PpIX and Hypericin. U-937 cells were irradiated (with and without ALA) and stored at room temperature. An LED lamp with a maximum peak of 637nm was used for ALA-PDT as a light source. A Na-Li lamp with a wavelength region of 560-730nm was used for Hypericin-PDT as a light source. We measured cell viability, the number of viable cells and ATP luminescence. As a result, it is evident that the irradiation time in the most effective PDT is equal to the time of the highest ATP level in the cells in ALA-PDT. This study suggests that it is possible to obtain suitable PDT conditions inducing apoptosis by measuring the ATP level in ALA-PDT. On the other hand, ATP level in Hypericin-PDT was increased with the decreasing in the cell viability. Hypericin-PDT induced apoptosis just after irradiation.