Effects of photodynamic therapy with azulene on peripheral blood mononuclear cell viability and singlet oxygen formation.

Abstract

We aimed to investigate the effect of azulene on peripheral blood mononuclear cells (PBMCs) viability and singlet oxygen formation. 1 × 105 PBMCs were cultured in a 96-well plate in RPMI-1640 supplemented with 10% FBS (37 °C, 5% CO2) for 24 h. Each well was treated for 30 min with each azulene concentration between 0-500 μM and activated by a 625 ± 5 nm light emitting diode (power 20-23 mW) at energy densities of 0-200 J/cm2. MTT cell viability was recorded using a spectrophotometer at a 570 nm. 9,10-Dimethylanthracene (DMA) was utilized for the measurement of singlet oxygen, using a fluorescence spectrophotometer at 375 and 436 nm as the excitation and emission wavelengths, respectively. Optical density, relative fluorescence units were compared using one-way ANOVA and a post-hoc test. The correlation between the cell number and singlet oxygen amount was analyzed by the Spearman correlation test. Azulene at all concentrations with 4.2 J/cm2 light significantly induced singlet oxygen formation. 15 μM azulene with 4.2, 100, or 200 J/cm2 light significantly reduced PBMC viability. The inverse relationship between the cell viability and singlet oxygen amount was observed. An optimum azulene concentration + red light energy density decreased PBMC viability via singlet oxygen formation.