Array analysis reveals induction of redox stress response gene expression in human reconstructed epidermis (EpiDermTM) exposed to topical HOCl. (a) Dose response relationship of HOCl-induced cytotoxicity (annexin V-PI flow cytometry) in HaCaT keratinocytes exposed to HOCl (0–250 μM; in PBS, 1 h) followed by postexposure culture (23 h) in regular medium. Panels display representative measurements; numbers in quadrants: percentage of viable cells (AV‐negative, PI‐negative) from a total of gated cells (mean ± SD, n = 3); bar graph: numerical analysis (normalized to viability of untreated control). (b–d) Human reconstructed epidermis [EpiDerm™; 9 mm diameter in 6 well format; see image insert (panel b)] was treated topically (100 μM HOCl in PBS, 30 min or 6 h, continuous exposure) and cultured until time of harvest, followed by Oxidative Stress Plus RT2 Profiler™ PCR Array analysis; scatter (panel b) and volcano (panel c) plots depict differential gene expression [(HOCl-exposed relative to PBS control) cut-off line: expression differential ≥ 2; p value < 0.05; red dots: upregulated] as presented by tabular summary (panel d). For bar graph depiction, quantitative data analysis employed ANOVA with Tukey's post hoc test; means without a common letter differ from each other (p < 0.05). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)