Interleukin 1α after exposure to SLS is time and dose dependent in normal human keratinocytes in colture

Interleukin-1alfa is involved in the biological response to irritants as one of the most important inflammatory mediators. The aim of the present study was to evaluate IL-1alfa production after exposure to sodium lauryl sulphate (SLS) from cultured keratinocytes, representing a model which enables the assessment of the in vitro effects of SLS epidermal cells independently from the skin immune system and barrier alterations. Normal human keratinocytes from plastic surgery were grown in serum free medium. At subconfluency, cells were treated with SLS doses ranging from 0.00001% to 0.005%. After one hour exposure the medium was changed. At different time-points the supernatant was collected for ELISA, and cells were harvested for Western blot analysis of pro-IL-1alfa and IL-1 alfa. Extracellular secretion of IL-1alfa from keratinocytes was increased in a dose-dependent manner following SLS treatment. The release of IL-1alfa starts at 15 minutes after exposure to SLS (IC50) reaching a maximum at 3 hours. Western blot analysis showed a down regulation of pro-IL-1alfa at 1 hour. Decrease was evident 1 hour after SLS treatment and was maximal at 12 hours.