Advances in corneal stem-cell transplantation in rabbits with severe ocular alkali burns

To evaluate the efficacy of autologous corneal epithelial sheet implantation in restoring transparency of rabbit corneas severely injured by alkaline and the effect of photocoagulation in arresting corneal neovessel ingrowth.

Ophthalmology Department, School of Biomedical Sciences, Universidad Austral, Buenos Aires, Argentina.

Limbal stem-cell deficiency (LSCD) was induced in 14 rabbits by alkali burns. A limbal cell biopsy was done in the contralateral eye, and the cells were cultured on a fibroblast feeder layer grown on autologous clotted platelet-poor plasma or commercial fibrin for 21 days. Anterior keratectomy was followed by suturing corneal cell sheets over the stroma. If regrowth of vessels occurred, argon laser photocoagulation was applied to them. Rabbits were killed at 30, 60, 90, 180, and 360 days and the corneas processed for histopathology and inmunohistochemistry.

A small (2.5 mm(2)) limbal biopsy achieved stem-cell replication in vitro. Corneal clarity and epithelial defects evolved with a trend toward improvement. There was a significant reduction in corneal neovascularization. Histology showed a multilayered stratified epithelium including several epithelial-like cells with clear cytoplasm in the deepest part. There were no signs of intraepithelial mucin cells on the implanted corneas. Immunohistochemical results showed expression of cytokeratins 3 and 12 in the central corneal epithelium and an absence of cytokeratin 19.

Autologous limbal epithelial cell transplantation improved the corneal surface in eyes with LSCD. Photocoagulation of neovessel ingrowth was effective over the 1-year follow-up. Results may facilitate the application of this technique in patients.