Category: Technical References, EpiDerm
501. INHIBITING THE EFFECTS OF OXIDATIVE STRESS VIA TOPICALLY APPLIED ANTIOXIDANT FORMULATIONS.
Betteridge1, J.W., Blenkiron1, P., Flood2, J., Johnson2, M., Sun2, Y., Zeller3, A., Zhu2, C. 1P&G Beauty, Egham, UK; 2Cincinnati, Ohio, USA; 3Marly, Switzerland.
Summary:
This study by researchers at the P&G Beauty Division of The Procter & Gamble Co. demonstrated that MatTek's EpiDerm in vitro human skin tissue equivalent is an excellent human skin model for measuring the ability of topically applied antioxidant skin care formulations to suppress the generation of free radical species when the skin models are exposed to environmentally-induced oxidative stress.
Environmentally generated reactive oxygen species (ROS) are increasingly considered to be a major source of oxidative stress for the skin, attacking proteins and membrane structures. ROS can also react with stratum corneum lipids to form lipid peroxide species (LPOs), which have links to premature aging and ultimately, DNA adducts. The presence of LPOs in skin can therefore be viewed as a biomarker for oxidative damage.
Scavenging antioxidants can reduce ROS damage by breaking or ‘quenching’ the free radical chain reaction. This study explores the ability of topically applied antioxidant formulations to inhibit ROS generation in tissue exposed to different sources of environmental oxidative stress. The study also aims to determine the protective effect of antioxidants for reducing lipid peroxidation.
Fluorescence Imaging: Living skin equivalents (LSE) (Epiderm 200, MatTek) were separately treated with an antioxidant formulation with or without SPF 15 or vehicle control, then doped with a radical visualization tag. Samples were then exposed either to UV irradiation or automotive emissions and imaged using a fluorescence microscope.
Lipid Peroxide Analysis: Tape strips were collected from the foreheads of human volunteers, following treatment with antioxidant formulation with or without SPF 15 or a no treatment control. After exposure under a solar simulator, sebum on the tape was extracted and LPO species were quantified spectrophotometrically.
Fluorescence imaging generated coloured intensity maps of ROS in skin tissue for each sample. Fluorescence signals were used to calculate the % quenching of ROS generated by UV/automotive emissions for each antioxidant formulation vs control. In this study, topically applied antioxidant formulations were found to significantly inhibit ROS formation in tissue vs. a no-antioxidant control (p<0.05). A similar effect was noted for automotive emissions.
LPO formation was successfully inhibited by the antioxidant/SPF system. Versus a no treatment control, the full formulations were found to suppress UV-induced LPO production in sebum by 25% (antioxidant package), and 75% (antioxidants + SPF 15) respectively.
Using a dual method approach, P&G Beauty scientists demonstrated that topically applied antioxidant skin care formulations can suppress the generation of free radical species in skin models (EpiDerm) exposed to environmentally-induced oxidative stress and inhibit the formation of skin-damaging lipid peroxide species.
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EpiDerm Reconstructed Human Epidermis (RhE) Data Sheet
EpiDerm Specifications
EpiDerm Technical References
Applications: Antioxidants, Biomarker research, Reactive oxygen species (ROS)
Keywords: Antioxidant skin care formulations, Biomarker, Biomarkers, EPI-200, EpiDerm, EpiDerm 200, Free radical species, Lipid peroxide species (LPOs), Oxidative stress, ROS, Reactive oxygen, Reactive oxygen species
Materials Tested: Antioxidants, SPF 15
