Modulation of cutaneous carotenoids content by ozone exposure

Ozone (O3) is a harmful air pollutant to which we are constantly exposed. Given its strong oxidizing effects and pervasiveness in the air we breathe, O3 is especially damaging to target organs in the respiratory system (e.g., lungs) and the integumentary apparatus (e.g., skin). Both of these systems act as a barrier and are able to limit the penetration of atmospheric pollutants into the body. In this regard, skin—the largest and main barrier against atmospheric intrusions—offers continuous protection against environmental intrusions. The skin is equipped with several defensive molecules that act as protective intracellular antioxidants against oxidative intrusions, including O3. Among these antioxidants are carotenoids, a family of lipophilic phytonutrients that are abundant in fruits and vegetables. It is well established that carotenoids accumulate in the epidermis layer of the skin, where they confer protection against oxidative intrusions and modulate inflammation, and that there is a direct correlation between skin and serum carotenoids level. The present study aimed to evaluate the variations in carotenoid content present in human skin prior to and after O3 exposure in 141 human subjects. Carotenoids were measured non-invasively using a resonance Raman spectroscopy (RRS)-based photonic device (Pharmanex BioPhotonic Scanner (BPS) Nu Skin Enterprises). In each volunteer, RRS skin carotenoids were determined at baseline and after 15 and 30 min of exposure to O3 0.8 ppm. The data obtained have an indicative value for individual variations in the cutaneous carotenoids, which have been shown to correlate with plasmatic contents. After the first 15 min of O3 exposure, there was a modulation of skin carotenoids, confirming their importance in the maintenance of cutaneous redox homeostasis.