ROLE OF CYTOKINE AND NITRIC-OXIDE IN THE INFLAMMATORY RESPONSE PRODUCED BY SULFUR MUSTARD (HD)

We have determined by immunocytochemistry the levels of interleukin-1 beta; (IL-1 beta) in cultured human epidermal keratinocytes (NHEK) fol lowing exposure to HD. Human skin keratinocytes release significant nu mbers of IL-1 cytokine as determined by the Quantikine(TM) Interleukin -1 beta kit, an enzyme-linked immunosorbent assay (ELISA) procedure. E xposure of NHEK [similar to 10(6)-10(7) cells, to HD (2 mM) and preinc ubation for 3 h at 37 degrees C] results in significant changes in IL- 1 activation. In neonatal NHEK exposed to HD, IL-1 beta is decreased. Conversely, in adult breast NHEK exposed to HD, IL-1 beta is increased . Nitric oxide ((NO)-N-.) has been implicated as the effector molecule that mediates IL-1 beta. To confirm the involvement of (NO)-N-. in th e expression of the IL-1 beta, electron paramagnetic resonance (EPR) s pectroscopy was employed. EPR detectable iron-nitrosyl complex in NHEK exposed to HD (18 h post exposure to 1 mM HD) were measured, and the generation of (NO)-N-. and this induced complex was blocked by N-omega -nitro-L-arginine (L-NOARG), a competitive inhibitor of nitric oxide s ynthase (NOS). Our results show the release of nitric oxide during IL- 1 cytokine expression when keratinocytes are exposed to HD. Based upon this work, it appears possible that IL-1 could be used as a specific marker for epidermal cytoxicity in mechanistic studies of the toxicity of HD and in defining interventive and therapeutic regimens against H D vesication.