Inflammatory Cytokine Expression Patterns in Rat Skin Exposed to JP-8 Jet Fuel

Abstract

One of the main complaints of personnel exposed to JP-8 jet fuel is irritant dermatitis. The purpose of this investigation is to describe the JP-8 induced inflammatory cytokine response in skin over various periods of exposure. JP-8 jet fuel or acetone control (300 μL) was applied to the denuded skin of rats once a day for up to seven days. Skin samples from the exposed area were collected after one, three, five and seven days of exposure. RT-PCR was performed utilizing total skin RNA to examine the expression of various inflammatory cytokines. The mRNA’s for the chemokines CXCL1, 2, 3 and 10, as well as CCL3, 5, 11 and 20 were variably modulated during the course of exposure, favoring the expression of those that attract PMN. IL-1β and IL-6 mRNA’s were significantly induced by five days, while IL-10 was not significantly different from control at any time point. Paradoxically, skin IL-6 protein content was found to decrease continually throughout the time course as determined by ELISA. Data from the present study indicates that repeated JP-8 exposure induces numerous proinflammatory cytokines in skin that tend to favor neutrophil accumulation. The increased expression of these cytokines and chemokines may lead to increased inflammatory infiltrate and injury of the skin, resulting in JP-8 induced irritant dermatitis.