Expression of IL-10, TGF-β and TNF-α in cultured keratinocytes (HaCaT Cells) after IPL treatment or ALA-IPL photodynamic treatment

Background: Depending on the light dose and concentration of photosensitizer for photodynamic treatment (PDT), a multitude of dose-related events are demonstrable in PDT-treated cells. Sublethal doses may result in the alteration of cytokine release and consequently modify immune actions, rather than cause cell death. Objective: The purpose of this study was to investigate cytokine expression in cultured HaCaT cells after intense pulse light (IPL) treatment or PDT utilizing 5-aminolevulinic acid (ALA) and IPL at sublethal doses. Methods: Cultured HaCaT cells were treated with either IPL only (4, 8 and 12 J/cm²) or ALA-IPL PDT (100 μ mol/L of ALA; 0, 4, 8, and 12 J/cm² of IPL). The expression of IL-10, TGF- β₁ and TNF-α was investigated by reverse transcription-polymerase chain reaction and enzyme linked immunosorbent assay. Results: IL-10 protein increased up to 5.95-fold after IPL treatment and up to 2.85-fold after PDT. TGF-β₁ mRNA and protein showed slight increases after both IPL treatment and PDT, of which the latter induced slightly larger increases. TNF-α mRNA and protein showed no induction or reduction after PDT. Conclusion: Increased expressions of IL-10 and TGF-β₁ was observed after PDT. The induction of IL-10 may contribute to the anti-inflammatory effect, which explains the therapeutic benefit of PDT for inflammatory dermatoses, and that of TGF- β₁ may be related to the therapeutic effect for psoriasis. The finding that IL-10 induction was more marked after IPL treatment than after PDT suggests that other mechanisms than IL-10 induction in keratinocytes after PDT may participate in the anti-inflammatory effect of PDT. (Ann Dermatol (Seoul) 21(1)12∼17,2009).