Stimulation of keratinocyte migration by growth factors.

Migration of keratinocytes from the wound edge is thought to be one of the critical features of reepithelialization. A quantitative migration assay was carried out using normal human keratinocytes. Keratinocytes, seeded on 12 well plates, were grown in serum free, keratinocyte growth medium (KGM, Curabo Co) with 0.08 mM Ca2+. The medium was switched from KGM to keratinocyte basal medium (KBM) 6 h prior to the wounding. Half of the plate's confluent monolayer of keratinocytes was removed with razor blade, and the remaining keratinocytes were incubated in KBM for 16 hrs in the presence of indicated growth factors. After incubation, the cells were fixed and counted at 100 magnification. Migration was quantitated by counting the number of cells in ten successive 125-microns zones. Transforming growth factor alpha (TGF-alpha), acidic and basic fibroblast growth factor (aFGF, bFGF), keratinocyte growth factor (KGF), hepatocyte growth factor (HGF), and insulin-like growth factor-I (IGF-I) stimulated the migration of keratinocytes, while TGF-beta suppressed it.