The effects of epithelial viability on stromal keratocyte apoptosis in porcine corneas stored in Optisol-GS

Purpose: To investigate the effect of corneal epithelium on the viability of corneal stromal keratocytes in Optisol-GS. Methods: After sterilization, corneoscleral buttons were excised and stored in Ciptisol-GS for various time periods. Group 1 corneas (n = 40) underwent mechanical corneal epithelial debridement before storage while group 2 corneas (n = 40) were stored with intact epithelium. Changes in corneal thickness, keratocyte density, and keratocyte apoptosis were investigated immediately, at 4 hours, and on days 1, 21 31 5, 7, and 14 in the preservation medium. The differences between group 1 and 2 corneas were analyzed. Results: Corneal thickness increased significantly in the second week of preservation in both groups, though more substantially in group 1. Significant corneal epithelial apoptosis was noticed in the first week in group 2 corneas. Corneal stromal keratocyte density decreased with prolonged preservation time. DNA laddering was detected by ligation-mediated polymerase chain reaction throughout the experiment periods in both groups, but the increase of keratocyte apoptosis was more significant after 5 days of preservation, especially in group 1. Conclusions: Stromal keratocytes underwent apoptosis in Optisol-GS. The absence of corneal epithelium during preservation further increased the stromal keratocyte apoptosis.