150 Skin damage induction by atmospheric particulate matter (PM0.3-2.5)

Abstract

Irritant damage to the permeability barrier elicits a cascade of responses that could be investigated by minimally invasive in vivo methods providing different information on biochemical and functional levels. Recent studies have shown that parallel to impairment of the barrier function and reduction of the natural moisturising factor (NMF), irritants such as the anionic detergent sodium lauryl sulfate (SLS) influence the corneocyte surface topography, investigated by atomic force microscopy and expressed by the Dermal Texture Index (DTI). To extend these findings, we investigated the early and late effects of different water soluble irritants on the barrier function, DTI, NMF and primary cytokine levels in healthy volunteers exposed to 60% N-propanol, 0.5% SLS, 0.15% sodium hydroxide, 2.0% acetic acid and occlusion with water in a controlled tandem repeated irritation test (TRIT) over 96 h. The irritant response was assessed by measuring erythema, transepidermal water loss (TEWL) and capacitance at baseline, 24 h and 96 h later; the cytokine levels, NMF and DTI were assessed in tape strips, collected at the same time points from the irritant-exposed and non-exposed sites. The magnitude of effects exerted by the irritants on the barrier integrity and properties, primary cytokine levels and DTI, found in the study, differed significantly, based on the chemical characteristics. The changes in DTI correlated with the NMF levels while being less influenced by inflammation. Though the observed differences may be influenced by the applied irritant concentration, our results confirm the need for a multi-parametric approach in the characterization of the irritant-specific barrier response and identification of sensitive outcome parameters for studying skin irritation in vivo.