Antiphotoaging Effects of Light-Emitting Diode Irradiation on Narrow-Band Ultraviolet B–Exposed Cultured Human Skin Cells

Abstract

Antiaging effects of light-emitting diodes (LEDs) have been clinically demonstrated using one or two wavelengths. The mechanism is unclear. To examine direct and indirect photobiomodulation effects of LEDs on narrow-band ultraviolet B (NB-UVB)-induced photoaging using seven different wavelengths alone or in combination. Four LED wavelengths were chosen based on type I collagen and metalloproteinase (MMP)-1 expression. NB-UVB-irradiated fibroblasts or keratinocytes were irradiated using these four wavelengths. The expression of collagen and MMP-1 in fibroblasts with or without conditioned medium from LED-irradiated keratinocytes and the expression of proinflammatory cytokines in the LED-irradiated keratinocytes were examined. Irradiation with four wavelengths (630, 660, 830, and 850nm) significantly increased the number of viable fibroblasts. These four wavelengths also increased type I collagen expression, particularly four combinations (630/830, 660/850, 630/850, and 660/830nm). The fibroblasts cultured with the keratinocyte conditioned medium, particularly with a combination of 630/850 or 660/830nm, increased collagen levels. Low tumor necrosis factor alpha (TNF-α) and high transforming growth factor beta 1 (TGF-β1) expression was detected in the LED-irradiated keratinocytes. The combination of 630/850- or 660/830-nm irradiation led to better direct and indirect antiphotoaging outcomes than single LED wavelengths in NB-UVB-irradiated cultured normal human skin cells.