Fig. 2

Migrating epithelia at 24 and 72 h after scraping the same area. a Photomicrographs demonstrating the method used to measure the distance of migration of epithelial cells. Four scratches on the glass were used as coordinates (arrowheads). The photograph on the left was taken 24 h after scraping, and the photograph on the right was taken at 72 h. The epithelial front is indicated by the green line, and the margin of the stratified region is indicated by the blue line. Both the epithelial front and the margin of the stratified region migrated upward. The distances of migration for both the migrating front and the stratified region were measured along randomly selected lines (5 yellow lines) perpendicular to the initial start line (generated by scraping), and the average moving distance was calculated. The change in the leading edge (LE) was calculated as ΔLE = LE1 − LE2, and the change in the stratified region was calculated as ΔSt = St1 − St2. b The migrating epithelia at 24 and 72 h after scraping. All the photographs are of the same area. The epithelia migrated upward during this 48-h period. Green line wounded edge of the cell sheet. Yellow line front margin of the stratified region. Left phase-contrast micrographs. Center Hoechst-stained specimens. Right merged images. c Comparison of the average migrated distances between the three methods (removal of stencils, scratch, and scrape). The experiments were performed in triplicate, and each experiment included at least three samples studied with each method. The values obtained by the scratch method were used for the control, and the migration distances observed following stencil removal and the scrape method are shown as ratios relative to the control. Error bars indicate SEMs. *p < 0.001; **p < 0.017