Bloom, E., M. Sznitowska, J. R. Polansky, H. I. Maibach. Growth Stimulation of Cultured Cells Following Irritant Exposure. The Toxicologist. February 1992. 12(1):111 (Abstract #359).

sodium dodecyl sulfate - 151-21-3; Triton X-100 - 9002-93-1; phenol - 108-95-2; ethyl phenylpropiolate - 2216-94-6

Skin irritation following chemical exposure is a complex process which results in a number of physiological/biochemical changes. One of the most consistently observed effects of irritant reactions in vivo is an increased rate of cell division and epidermal thickening. To better understand the mechanisms of irritant action, we have investigated a number of irritants for their in vitro ability to affect cell division after a brief exposure at sublethal doses using cultured human keratinocytes and skin fibroblasts. Sodium dodecyl sulfate (SLS), triton X-100, ethyl phenylpropionate, phenol, and tetradecanoyl phorbol acetate stimulate cultured keratinocyte division after a 1 hour exposure to irritants at sublethal doses (10(-8) to 10(-6) M). For keratinocytes, the observed maximal stimulations at sublethal doses were from 25 to 100%. Fibroblasts gave similar results. At higher doses and/or longer exposures irritants tend to decrease cell growth potential, as has been reported by a number of investigators. The possibility that released soluble factors were involved in the observed stimulation of cell division was next investigated using conditioned media from cells exposed to SLS at sublethal doses. The observed stimulation (20-30%) of cell division from conditioned media was somewhat less than the stimulation observed in the directly injured cells (approx. 50%) but indicated the presence of active media factors. Biochemical studies of the media factors may provide useful information to understand the mechanisms for increased cell division in vitro and in clinical conditions in which acute and chronic irritant/injury mechanisms appear to play a role.