Figure 4. Hypoxia-promoted keratinocyte galvanotaxis is preconditioning-time dependent.

The keratinocytes were exposed to 2% O₂ for 3, 6 or 12 hours and then stimulated with an EF of 50 mV/mm for another 3 hours under normoxic conditions. (A–H) The migration trajectories of keratinocytes guided by EF (E–H) or not (A–D) under normoxic culture conditions (A, E) or 2% O₂ preconditioning (B–D, F–H). (I–L) Analysis of the directedness, trajectory speed, displacement speed and X-axis speed of keratinocyte migration. The data are from at least 100 cells in 3 independent experiments and are shown as the mean ± SEM. *, p < 0.05; #, p < 0.01 compared with the cells without hypoxia pretreatment.