Cytokine Deposition Alters Leukocyte Morphology and Initial Recruitment of Monocytes and γδT Cells After Corneal Injury

PURPOSE. An in vivo mouse model reproducibly induces recurrent epithelial erosions in wildtype mice spontaneously 2 weeks after a single 1.5-mm corneal debridement wound made with a dulled blade. When 1.5-mm wounds are made by a rotating burr so that the corneal epithelial basement membrane is removed, corneas heal without developing erosions. Here, we characterize differences in cytokine deposition and changes in leukocytes between 0 and 6 hours after dulled-blade and rotating-burr wounding. METHODS. BALB/c mice were used to study 1.5-mm corneal wounds made using a dulled blade or a rotating burr. Mice were studied immediately after wounding (0 hour) and at 6 hours in vivo and in vitro in organ culture. Corneas, corneal extracts, and collagenase digests from naive and wounded mice were used for three-dimensional (3D) confocal imaging, cytokine arrays, and flow cytometry. RESULTS. Confocal imaging showed CD45, a protein derived from leukocytes, accumulates at the wound edge by 3 and 6 hours after wounding in vivo but not in vitro with more CD45 accumulating after dulled-blade compared with rotating-burr wounds. Morphologic changes occurred in CD45+ leukocytes and higher levels for several cytokines were detected in the stromal wound bed within minutes following dulled-blade wounds. Flow cytometry showed significantly more monocytes (CD45+/CD11b+/Ly6C+) and gamma delta T cells (CD45+/GL3+) recruited into the corneas of mice with dulled-blade wounds by 6 hours. CONCLUSIONS. Differences in cytokine-driven leukocyte responses are seen after dulled-blade debridement compared with rotating-burr injury.