MEASUREMENT OF INFLAMMATORY MEDIATORS PRODUCED BY HUMAN KERATINOCYTES INVITRO - A PREDICTIVE ASSESSMENT OF CUTANEOUS IRRITATION

Two inflammatory mediators, interleukin 1-alpha (IL1-alpha) and prostaglandin E2 (PGE2), were determined by radioimmunoassay in both intracellular and extracellular compartments from normal human keratinocytes in high-density culture. Cells were subjected to different inflammatory stimuli: UVB irradiation and detergent injury by sodium dodecyl sulphate (SDS). UVB irradiation produced intracellular IL1-alpha synthesis, and its dose-dependent release in the medium. Similar results were obtained with SDS. The SDS stimulus was time dependent, and the following mechanisms were observed: (i) increased production of intracellular inflammatory mediators; and (ii) progressive release of these mediators in the medium. With SDS, production and release of PGE2 peaked below the lethal doses (assessed by the neutral red bioassay). Therefore, the measurement of IL1-alpha and PGE2, both intra- and extracellularly may be a useful in vitro method for assessing the irritative potential of topically applied agents.