Allergic and irritant skin reactions caused by topical exposure to permanent hair dyes are a common problem. For regulatory and ethnical purposes, it is required to perform chemical safety assessment following the replacement, reduction, and refinement of animal testing (3Rs). Permanent hair dyes are formed by a mixture of ingredients that vary from low to extreme skin sensitizing potency and that inter-react to form unknown by-products. Because of the complex reaction, this cytotoxic mechanism has not yet been elucidated and is the subject of this study. Here, we topically exposed p-phenylenediamine (PPD), Resorcinol (RES), Hydrogen Peroxide (H₂O₂) alone or as a mixture to RhE and evaluated parameters related to skin irritation such as epidermal viability, keratinocytes damage, barrier loss and IL-1 α. Our data indicates that ingredients tested alone did not lead to an increase of cytotoxic parameters related to skin irritation. However, when the mixture of PPD/H₂O₂/RES and PPD/H₂O₂ was applied to the RhE, some of the parameters such as morphological changes including the presence of apoptotic cells, barrier loss and increased IL- 1 α release were observed. The results indicate that the mixture of ingredients used in permanent hair dyes have an irritant effect in RhE while the ingredients alone not.

由局部暴露于永久染发剂引起的过敏和刺激性皮肤反应是一个普遍的问题。出于法规和种族的目的，要求在替换，减少和完善动物试验（3R）之后执行化学安全性评估。永久性染发剂由多种成分组成，这些成分的变化范围从低到极高，对皮肤的增效能力很高，并且相互反应形成未知的副产物。由于反应复杂，这种细胞毒性机制尚未阐明，是本研究的主题。在这里，我们局部暴露了对苯二胺（PPD），间苯二酚（RES），过氧化氢（H ₂ O ₂）单独使用或与RhE混合使用，并评估了与皮肤刺激有关的参数，例如表皮活力，角质形成细胞损伤，屏障丧失和IL-1α。我们的数据表明，单独测试的成分不会导致与皮肤刺激有关的细胞毒性参数增加。但是，当将PPD / H ₂ O ₂ / RES和PPD / H ₂ O ₂的混合物应用于RhE时，某些参数（例如形态变化）包括凋亡细胞的存在，屏障丧失和IL-1α升高。观察到释放。结果表明，用于永久染发剂的成分混合物对RhE具有刺激作用，而单独的成分则没有。