ABSTRACT
BACKGROUND: Emerging clinical evidence suggests that intense pulsed light (IPL) treatment may exert some beneficial effects on photoaged skin. The molecular mechanisms underlying this IPL effect have not been fully elucidated. OBJECTIVE: To examine the effects of IPL irradiation on normal human dermal fibroblasts grown in contracted collagen lattices. METHODS: Human skin fibroblasts cultured in contracted collagen lattices were irradiated with IPL with triple pulses of 7 ms with a pulse interval of 70 ms and fluences of 20, 50, and 75 J/cm(2). Twenty-four hours after the irradiation, cell viability, messenger RNA (mRNA), and protein levels of extracellular matrix proteins (e.g., collagen I, collagen III, and fibronectin) and transforming growth factor beta-1 (TGF-beta1) were evaluated using dye exclusion, real-time reverse transcriptase polymerase chain reaction, and enzyme-linked immunosorbent assay, respectively. RESULTS: A dose-dependent increase in viable cells was demonstrated after the IPL irradiation. There was no significant change in mRNA levels of collagen I and fibronectin. Upregulated expression of collagen III and TGF-beta1 in dermal fibroblasts was verified. CONCLUSIONS: The analytical results presented here provide a potential mechanistic explanation for the mechanism of clinical photorejuvenation effects of IPL that involves the increase of extracellular matrix construction by upregulating the gene expressions of collagen III and TGF-beta1.
