Transcriptional response of porcine skin to sulfur mustard

Sulfur mustard (HD) is a potent alkylating agent that induces cutaneous injury. The molecular mechanisms of cutaneous injury are not completely understood, and the molecular pathways involved in post-exposure wound healing are not well characterized. To elucidate these molecular pathways for the purpose of identifying potential therapeutic targets, we used oligonucleotide microarrays to identify gene expression profile changes induced by HD in porcine skin, an established animal model of HD injury and wound healing. Female Yorkshire crossbred pigs were exposed to neat HD to generate a superficial dermal (second degree) injury. Skin punch biopsies were collected at 1 h, 2 h, 4 h, 24 h, 48 h, 72 h, 7 d, 14 d or 21 d post-exposure. Biopsies were scored for histopathology, and RNA extracted from biopsies was used for microarray analysis. Gene expression profiles were analyzed for significant temporal response to HD by analysis of variance (false discovery corrected p<0.05). Gene expression profiles were also correlated (Pearson linear correlation |r|>0.7, false discovery corrected p<0.05) to histopathology scores to identify molecular pathways significantly correlated with specific clinical endpoints of injury and repair. Several pathways linked to aspects of inflammatory response and cell cycle checkpoint regulation were altered by HD exposure through 72 h. Several of these inflammatory pathways were highly correlated with clinical endpoints assessed through 72 h, including epidermal necrosis and vesicle formation. Pathways linked to inflammation were also highly correlated with 7-21 d total histopathology scores, suggesting that inflammation is continual through the course of injury and healing. Specific therapeutic targets were identified within these inflammatory pathways, and potential therapeutics were also identified for future drug screening efforts.

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