Figure 2.

Initial events after a mechanical injury on an epithelial monolayer under culture conditions. A mechanical scratch determines three main initial events: (i) death and lysis of the injured cells, with release of cellular content, (ii) development of mechanical stress, and (iii) loss of cell-cell contacts of the remaining living cells at the wound borders. Among the intracellular molecules released, some that play a role in wound healing in in vitro conditions could be ATP [87, 88] and growth factors (GFs) [89, 90]. ATP, H₂O₂, and eicosanoids are released by the surviving border cells in response to stress [87, 88]. The loss of cell-cell contacts at the free wound edges stimulates migration and activates growth factor receptors [91, 92]. The three types of events trigger different responses of the surviving cells, frequently propagated to the rest of the monolayer as physical and/or chemical gradients (blue arrows).