Molecular and histological responses in rat skin exposed to m-xylene

Solvents, surfactants, cutting fluids, hydrocarbons; and oils cause skin irritation by incompletely understood mechanisms. This study examined histological and molecular changes in rodent skin caused by brief topical exposures to m-xylene. At 0, 1, 21 4, and 6 h after 1-h exposure, skin samples were removed and analyzed for histopathological changes and interleukin-1alpha (IL-1alpha) and inducible nitric oxide synthase (iNOS) protein levels. Histopathological changes (epidermal-dermal separation and granulocyte infiltration) and increases in IL-1alpha and MOS protein expression occurred during our observation period. IL-1alpha levels increased by 80% immediately after exposure and MOS levels increased about 60% 4 hours after exposure. Our study demonstrates that dermal exposure to m-xylene promotes IL-1alpha and iNOS production in skin and these proteins may serve as early indicators of skin irritation. (C) 2003 Wiley Periodicals, Inc.