Abstract
Purpose:
A population of leader cells was found to direct migration of lens epithelial cells in response to wounding. The current studies were carried out to determine 1) whether leader cells are involved in the response of the corneal epithelium to injury, and 2) test the hypothesis that leader cells are immune cells.
Methods:
1.5 mm debridement wounds were made manually in 8 week old BALB/c using one of two techniques: a rotating burr (RB) or a dulled blade (DB). Mice were either sacrificed at the time of wounding (Time 0, T0) or allowed to heal for 1 or 6 hrs. All eyes were fixed within 5-10 min after injury. Corneas were used for whole mount immunofluorescence studies to localize CD45 (the common leukocyte antigen), F4/80 (a monocyte marker), GL3 (an epitope present on γδT cells), and vimentin, at the leading edges of the wounded corneas. For each variable studied, no fewer than 3 corneas from 3 different mice were used.
Results:
CD45+ cells appear at the leading edge in the T0 corneas. T0 DB wounds recruit more F4/80+ cells compared to RB wounds and this difference persists through the 6 hr time point. Similar levels of F4/80+ cells were present at T0 and 1 hr after wounding. There were several detectable vimentin+GL3+ cells present at the leading edge at T0 and 1 hr post-injury for both RB and DB wounds. By contrast, after 6 hrs, GL3+ cells were absent after DB, and only rarely seen after RB wounding.
Conclusions:
The rapid migration of leader cells to the wound edge following mock cataract surgery in the lens is also seen in the cornea after manual debridement wounding. The numbers of leader cells recruited at T0 and 6 hrs after wounding varied depending on the type of wound. All of the leader cells are positive for CD45, with the majority being positive also for F4/80. A subpopulation of the leader cells are vimentin+GL3+ but these cells are more transient than the F4/80+ cells since they are largely absent by 6 hrs after wounding. Unlike the mouse cornea, the majority of the leader cells in the chicken lens wound model express vimentin. While the functions of these rapidly appearing immune cells is not clear, our studies indicate that wound healing in chicken and mouse and in diverse tissues including the lens and cornea share a similar property: rapid recruitment of immune derived cells to the leading edge.
Keywords: 482 cornea: epithelium •
765 wound healing •
480 cornea: basic science