Photoprotection of Cerium Oxide Nanoparticles against UVA radiation-induced Senescence of Human Skin Fibroblasts due to their Antioxidant Properties

Ultraviolet (UV) irradiation, particularly ultraviolet A (UVA), stimulates reactive oxygen species (ROS) production in the epidermis and dermis, which plays a major part in the photoageing of human skin. Several studies have demonstrated that cerium oxide nanoparticles (CeO 2 NP) can exhibit an antioxidant effect and free radical scavenging activity. However, the protective role of CeO 2 NP in skin photoageing and the underlying mechanisms are unclear. In this study, we investigated the effects of CeO 2 NP on UVA-irradiated human skin fibroblasts (HSFs) and explored the potential signalling pathway. CeO 2 NP had no apparent cytotoxicity, and could reduce the production of proinflammatory cytokines, intracellular ROS, senescence-associated β-galactosidase activity, and downregulate phosphorylation of c-Jun N-terminal kinases (JNKs) after exposure to UVA radiation. Based on our findings, CeO 2 NPs have great potential against UVA radiation-induced photoageing in HSFs via regulating the JNK signal-transduction pathway to inhibit oxidative stress and DNA damage.