Intense pulsed light rejuvenates UVB-induced photoaging in human keratinocytes and guinea pig skin by inhibition of ERK-AP-1-MMP pathway

Skin photoaging is predominantly induced by ultraviolet (UV) irradiation. Intense pulsed light (IPL) is a commonly employed non-ablative treatment for photoaging. However, the effects and mechanisms of IPL on UV-induced skin photoaging remain insufficiently understood. In this study, we aimed to examine the anti-photoaging effects of IPL and elucidate the underlying mechanisms. This study revealed that UV triggered extracellular signal-regulated kinases (ERK) together with c-jun NH2-terminal kinase (JNK), while selectively suppressed UV-induced ERK phosphorylation while activating JNK in human skin keratinocytes. The different ERK/JNK expression patterns induced by UV and IPL resulted in distinct c-fos/c-jun (activator protein 1) phosphorylation, cyclin D1 expression, and matrix metalloproteinase (MMP) secretion. In vivo, IPL inhibited MMP expression in guinea pig skin and promoted c-fos/c-jun phosphorylation, epidermal proliferation, and collagen remodeling. These findings indicated that ERK was involved in IPL rejuvenation by regulating c-fos, c-jun, cyclin D1, and MMPs, providing a potential target for skin rejuvenation.