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 NP) can exhibit an antioxidant effect and free radical scavenging activity. However, the protective role of CeO NP in skin photoageing and the underlying mechanisms are unclear. In this study, we investigated the effects of CeO NP on UVA-irradiated human skin fibroblasts (HSFs) and explored the potential signalling pathway. CeO 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 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.