Apoptotic cell death induced by 5-aminolaevulinic acid-mediated photodynamic therapy of hypertrophic scar-derived fibroblasts.

OBJECTIVE

To investigate the effects of 5-aminolevulinic acid (ALA)-mediated photodynamic therapy (PDT) on dermal fibroblasts from hypertrophic scars (HSs).

METHODS

HS samples were obtained from five patients who underwent surgery, and normal skin from healthy donors was used as a control. Dermal fibroblasts were isolated and cultured with various concentrations of ALA for 6 h. Intracellular protoporphyrin IX (PpIX) was measured by confocal microscopy. After 5 h of ALA treatment, cells were irradiated by a red laser (635 nm wavelength) at a power density of 10 mW/cm(2) with an energy density from 0.5 to 4 J/cm(2). Cell survival was measured by a CCK-8 Kit after 24 h. Cell death was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling and flow cytometric analysis of annexin V.

RESULTS

Intracellular PpIX accumulation was observed in fibroblasts from HS patients and healthy donors after ALA treatment. After laser irradiation, viable cells were decreased among both cell types in a dose-dependent manner with energy density. In addition, apoptotic cell death was observed with low dose PDT, whereas necrotic cells were increased by high dose PDT.

CONCLUSION

HS-derived fibroblasts efficiently accumulate PpIX after ALA treatment and can be eliminated via apoptosis by controlled laser irradiation.