Protective Effects of Polyvinylpyrrolidone-Wrapped Fullerene Against Nitric Oxide/Peroxynitrite-Induced Cellular Injury in Human Skin Keratinocytes.

Excess ultraviolet (UV) exposure accelerates skin inflammation, melanogenesis, wrinkle formation, photoaging, and carcinogenesis through oxidative stress and deoxyribonucleic acid damage. These deleterious effects to skin are closely associated with UV-induced reactive oxygen species (ROS) and reactive nitrogen species (RNS) produced via nitric oxide (NO) generation. RNS are known to be responsible for various skin disorders, such as erythema, melanin production, reduced barrier function, and psoriasis. These skin disorders are major cosmetic problems; RNS control, in addition to ROS control, is important for maintaining healthy skin. In the present study, we investigated the cytoprotective effects of polyvinylpyrrolidone-entrapped fullerene (C/PVP), a water-soluble ROS scavenger, against nitric oxide (NO) and peroxynitrite (ONOO)-induced human keratinocyte injuries. Protective effects of C/PVP on NO/ONOO-induced cellular damage and intracellular ONOO generation were evaluated using a NO donor S-nitroso-N-acetylpenicillamine (SNAP) in human skin epidermal HaCaT keratinocytes. Furthermore, the suppressive effect of C/PVP on UVB-induced generation of intracellular ONOO levels was also investigated. C/PVP exerted suppressive effects on intracellular increases in NO-induced ONOO generation and subsequent cellular damage. Additionally, C/PVP significantly decreased the UVB-induced generation of intracellular ONOO levels. These findings suggest that C/PVP could be useful as a cosmetics ingredient for prevention of skin injuries and/or dysfunction from NO/ONOO-induced effects in human skin keratinocytes.