Toxic and immunotoxic evaluation of permanent hair dyes using artificial skin: alternative measures for animal experimentation

• Grant number: 14/15224-4
• Support type: Scholarships in Brazil - Post-Doctorate
• Effective date (Start): November 01, 2014
• Effective date (End): August 15, 2017
• Field of knowledge: Health Sciences - Pharmacy
• Cooperation agreement: Coordination of Improvement of Higher Education Personnel (CAPES)
• Principal Investigator: Silvya Stuchi Maria-Engler
• Grantee: Thalita Boldrin Zanoni
• Home Institution: Faculdade de Ciências Farmacêuticas (FCF). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated scholarship(s): 15/23702-6 - MUTZ-3 derived Langerhans cells in human skin equivalents: a platform to elucidate the allergic potential and distinguish irritant exposure of ingredients used in permanent hair dyes, BE.EP.PD

Abstract

Hair dyes are products that represent worldwide a large amount of money for the cosmetic industries. Among the various types of dyes, permanent hair dyes accounts for about 80% of dyes used in global market. These dyes are based on oxidative reactions between a primary intermediate (ex. aromatic amines) and a coupler agent (ex. phenolic compounds) that reacts in oxidative conditions. This process requires a complex mechanism that involves different reactions that results in the formation of a colored compound capable of changing permanently the hair shaft. During a hair dying procedure, human skin is the primary route of exposure to these chemicals. Considering the exposed, the present project aims to evaluate the toxic and sensibilization potential of two hair dyes largely used in permanent hair dyes formulations, these are p-toluenodiamine (PTD) and p-aminophenol (MAF), precursor and coupler agent respectively.The reaction products between the ingredients in oxidative conditions will be analyzed using analytical methods such as liquid chromatography linked to mass spectrometry. Our goal is to determine the toxic potential of these compounds and its mixtures, guarantying advances to the understanding of these complex mixtures that are largely used by cosmetic industries. For this, first we aim to elucidate the toxic and sensibilization mode of action of PTD and MAF in oxidative conditions using H2O2.Therefore, molecular biology assays will be used to identify the specific pathway of cell death induction by each compound, and whether they interfere on the cell cycle. For this, we will use human primary skin cells such as keratinocytes and fibroblasts for the evaluation of the most toxic compound compared to its mixture, then the toxicity of these compounds will be analyzed after topical applying of the most toxic ingredients and its mixture in skin equivalents. Moreover the sensibilization potential will be investigated using imunocompetent skin equivalents. The development of both of these in vitro techniques should contribute globally to the establishments of new methodologies that are able substitute animal testing. Both techniques will be achieved by using our developed skin equivalents here in our laboratory in FCF-USP, SP. The development of an immunocompetent skin is a new methodology in Brazil, which promises to bring scientific and pioneering innovations in both, national and international levels, Finally this project aims to contribute to advances in understanding the allergenic and toxic potential of components regularly used in permanent hair dyes using very promising scientific innovative methodology's. (AU)