Vitamin C compounds mixture prevents skin barrier alterations and inflammatory responses upon real life multi pollutant exposure

Abstract Cutaneous tissues is among the main target of outdoor stressors such as ozone (O 3 ), particulate matter (PM), and ultraviolet radiation (UV) all involved in inducing extrinsic skin aging. Only a few reports have studied the multipollutant interaction and its effect on skin damage. In the present work, we intended to evaluate the ability of pollutants such as O 3 and PM to further aggravate cutaneous UV damage. In addition, the preventive properties of a cosmeceutical formulation mixture (AOX mix) containing 15% vitamin C (L‐ascorbic acid), 1% vitamin E (α‐tocopherol) and 0.5% ferulic acid was also investigated. Skin explants obtained from three different subjects were exposed to 200 mJ UV light, 0.25 ppm O 3 for 2 h, and 30 min of diesel engine exhaust (DEE), alone or in combination for 4 days (time point D1 and D4). The results showed a clear additive effect of O 3 and DEE in combination with UV in terms of keratin 10, Desmocollin and Claudin loss. In addition, the multipollutant exposure significantly induced the inflammatory response measured as NLRP1/ASC co‐localization suggesting the activation of the inflammasome machinery. Finally, the loss of Aquaporin3 was also affected by the combined outdoor stressors. Furthermore, daily topical pre‐treatment with the AOX Mix significantly prevented the cutaneous changes induced by the multipollutants. In conclusion, this study is among the first to investigate the combined effects of three of the most harmful outdoor stressors on human skin and confirms that daily topical of an antioxidant application may prevent pollution‐induced skin damage.