Research of ALA combined with HpD-PDT which induced S180 ascitic tumor cells, death, or apoptosis on cytology

Abstract

Objective: To ascertain the adequate dosage of ALA combined with HpD-PDT which induced tumor cell death or apoptosis on cytology. And to study the different effect of ALA-PDT and HPD-PDT used only. Methods: Rat ascitic tumor cells(S180) were randomly divided into several groups and incubated with ALA (20μg/ml, 40μg/ml, 80μg/ml, 160μg/ml), HPD (2.5μg/ml, 5μg/ml, 10μg/ml) and their combination dosages. 630nm light (total output 2W) was delivered to tumor cells at a constant fluence rate: 200mw/cm2 and a constant irradiated time period: 20 minutes. We set 3 groups (no photosensitizers or no irradiation or neither) to be the control groups. We used inversion microscopy to observe the morphological change of tumor cells and flow cytometry technology to detect the death or apoptosis of tumor cells during the experiment. Results: After irradiated with 630nm light on 20 minutes, S180 tumor cells incubated with the combination dosage of ALA 40μg/ml and HPD2.5μg/ml were induced highest rate of apoptosis. The rate of cells' early apoptosis was 2.54%, while the late apoptosis was 95.10% Conclusion: The combination dosage of ALA 40μg/ml and HPD2.5μg/ml (25% of constant dosage) used in the PDT treatment was the most adequate dosage on cytology.