PAI-1 immunoreactivity is evident in basal keratinocytes at the migratory front. Paraffin sections (5 μm) of control (A) and tiplaxtinin-treated (B) wounds were probed with PAI-1 antibodies 5 days after wounding. Images were taken with a 10× (left; dashed box indicates location of magnified image) and 20× (right) objective (D, dermis; E, epidermis, wound edge is indicated by arrows). (C, E, F) PAI-1 (1 nM), EGF (10 ng/mL), and tiplaxtinin (10 μM) were added to HaCaT monolayers at the time of scratch injury in serum-free media. Cells were incubated for 24 h, fixed, stained with crystal violet, and wound closure quantitated using an ocular grid (data are presented as mean±SEM; *p<0.05). (D) Subconfluent cells were infected with adenoviral constructs encoding either GFP (control) or PAI-1. Cells were allowed to reach confluence, scratch wounded, incubated for 24 h, fixed, stained with crystal violet, and wound closure quantitated using an ocular grid (data are presented as mean±SEM; *p<0.05). EGF, epidermal growth factor.