510 Complex phototoxic properties of a cigarette smoke extract on human keratinocytes

Sun exposure and cigarette smoke, studied separately, are two well-known environmental factors that accelerate skin aging. However, their combined effects has been poorly characterized. Some studies have determined smoke components can accumulate in the by contact or systemic effect after inhalation. Moreover, it is well-established solar rays penetrate epidermis dermis. Those could thus interact with one another skin. The aim of this study to assess phototoxic on skin, more precisely A extract (CSE) was obtained capturing soluble fraction smoke. performed a simulator at 14.5 29 kJ/m2 UVA, representing 15 30 minutes sun its zenith. CSE phototoxicity human keratinocytes using an MTS assay, establishing cellular metabolic activity. photo-oxidation fluorescent markers measuring ROS levels. total antioxidant capacity (TAC) also assessed. irradiation alone showed no cytotoxicity up maximal doses tested. highly when irradiated. Indeed, exposed 5% respectively 39±1% 2±17% viability (p-value<0.001). Photo-oxidation results indicate decrease type I slight increase II ROS. TAC test revealed capacities. Our synergistic toxicity between cells, caused part reaction. work still focussing deciphering mechanisms involved synergy.