Stimulation of the proliferation and differentiation of skin cells by ferrous ferric chloride from a distance.

Ferrous ferric chloride (FFC) is a distinct form of aqueous iron composed of a complex of ferrous chloride and ferric chloride that participates in both oxidation and reduction reactions, and stimulates the proliferation and differentiation of mammalian keratinocytes, melanocytes, and fibroblasts. However, it is not known whether FFC can stimulate their proliferation and differentiation without being added into culture media or painted on the skin. This study aims to clarify whether FFC can stimulate their proliferation and differentiation from a distance without being added to culture media. In this study, FFC-containing skin lotions were painted under the culture dishes (1 mm away from cells) or on the top of the covers of 1 to 5 polystyrene culture dishes (1 to 5 cm away) and tested for their proliferation- and differentiation-stimulating effects. FFC lotions stimulated the proliferation and differentiation of human keratinocytes, melanocytes, and fibroblasts from a distance of 1 mm to 1 cm. However, FFC lotions failed to stimulate the proliferation and differentiation of melanocytes from distances of 2 to 5 cm. Results using Teflon covers were similar to those of polystyrene covers. Moreover, the effects of FFC lotions painted on the top of the Teflon covers were completely lost by lead disks. These results suggest that FFC can stimulate the proliferation and differentiation of skin cells from a distance of 1 cm without being added into culture media through physical factors rather than chemical factors.