Myeloid-Derived Suppressor Cells Enhance Wound Healing in a Murine Model of Corneal Injury.

PURPOSE: Corneal injury is a leading cause of vision loss and demands rapid, coordinated regeneration. Myeloid-derived suppressor cells (MDSC), innate immunoregulatory cells that aid repair in peripheral tissues, have not been evaluated in corneal healing. We tested whether MDSC promote epithelial closure and temper postinjury inflammation.

METHODS

For scratch assays, 1.0 × 10 5 human corneal epithelial cells were cocultured with 1.5 × 10 6 MDSC or CD11b + Gr-1 - control cells, and wound areas at 18 and 24 hours were quantified in ImageJ. In vivo, corneal epithelial debridement was induced in BALB/c mice using an Algerbrush-II, followed by subconjunctival injection of MDSC or control cells (5 × 10 4 cells in 50 μL saline). Epithelial healing was assessed by fluorescein staining and slitlamp imaging at 6, 22, and 28 hours, with ImageJ analysis. At 28 hours, corneas were collected for real-time polymerase chain reaction and flow cytometry to assess inflammatory markers. On day 3, corneas were harvested for hematoxylin and eosin staining and histological analysis.

RESULTS

MDSC significantly enhanced human corneal epithelial cells migration in vitro versus controls. In vivo, MDSC delivery accelerated epithelial wound closure, reduced CD11b + Ly6G + neutrophil infiltration, and lowered corneal tumor necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β) expression compared with saline or CD11b + Gr-1 -  control cells. Histology confirmed restoration of epithelial integrity in MDSC-treated eyes.

CONCLUSIONS

MDSC expedite corneal epithelial repair and attenuate acute inflammation after injury. These findings identify a previously unrecognized reparative function for MDSC in the cornea and support their development as a cell-based therapy for ocular surface injury.