The effect of deferoxamine on the photodynamic reaction in human skin fibroblasts induced by δ-aminolevulinic acid

Abstract

Objective To investigate the effect of deferoxamine (DFO) on the photodynamic reaction in human skin fibroblasts co-cultured with δ-aminolevulinic acid (ALA). Methods Human skin fibroblasts were isolated from juvenile foreskin tissue and co-cultured in vitro with nothing (control group),2 mmol/L ALA,0.1 mmol/L DFO or ALA + DFO.Three hours later,the protoporphyrin IX (PpIX) levels in the fibroblasts were determined by high performance liquid chromatography with fluorescent detection (HPLC-FLD).Laser scanning confocal microscopy (LSCM) was used to observe the strength of fluorescence in the fibroblasts with the excitation of a 488 nm laser.The proliferation (absorbance ratio) and survival rate of cells were detected by MTT colorimetric methods and trypan blue staining respectively.The cellular PpIX positive groups were irradiated with a 632.8 nm He-Ne laser.Flow cytometry was used to calculate cellular apoptosis and necrosis. Results There was no significant difference between the cell absorbance ratio or survival rates of the four groups before He-Ne laser iradiation.No cellular PpIX was found in the control or DFO groups,while the cellular PpIX concentrations in the ALA and ALA + DFO groups were (0.47±0.04) μg/L and (0.85±0.08) μg/L respectively.After He-Ne laser irradiation,in the ALA and ALA + DFO groups the cellular apoptosis rates were 14.1% and 21.5% respectively,and the cellular necrosis rates were 2.7% and 3.0% respectively. Conclusions Neither ALA nor DFO affected the basic biological features of skin fibroblasts,but DFO could enhance the PpIX production and subsequent photodynamie reactions in human skin fibroblasts co-cultured with ALA. Key words: δ-aminolevulinic acid; Deferoxamine ; Fibroblasts; Photodynamic therapy; Protoporphyrin IX