Intense pulsed light rejuvenates UVB-induced photo-aging in human keratinocytes and guinea pig skin by inhibition of ERK-AP1-MMP pathway

Abstract

Skin photo-aging is mainly caused by ultraviolet (UV) irradiation. Intense pulsed light (IPL) is a widely used nonablative treatment for photo-aging, while the mechanism is unclear. Here, we investigate the anti-photoaging effects of IPL and the underlying mechanism. This study demonstrated that UV-triggered extracellular signal-regulated kinases (ERK) together with c-jun NH2-terminal kinase (JNK) while IPL suppressed ERK but activated JNK in human skin keratinocytes (hKCs). The different ERK / JNK expression patterns induced by UV and IPL resulted in different c-fos / c-jun(AP-1) phosphorylation, CyclinD1, and matrix metalloproteinase (MMPs) expression. Furtherly, treatment of hKCs with ERK inhibitor (PD98059) revealed that a certain dose of IPL at 17 Jcm² (IPL17) significantly promoted c-fos / c-jun phosphorylation by inhibiting the ERK pathway. IPL17 inhibited MMPs expression in guinea pig skin and promoted c-fos / c-jun phosphorylation, epidermal proliferation, and collagen remodeling in vivo. These findings indicated that ERK was involved in IPL rejuvenation by regulating c-fos / c-jun / CyclinD1 / MMPs, providing a potential target for skin rejuvenation.