Protection of Corneal Limbus from Riboflavin Prevents Epithelial Stem Cell Loss after Collagen Cross-Linking

Figure 1

Experimental scheme and examination of corneal epithelial healing and thickness. (a) Scheme of experiments: 5-bromo-2-deoxyuridine (BrdU) was injected intraperitoneally in rabbits on Day 7, and collagen cross-linking (CXL) performed on Day 0. On Day 1, corneas were evaluated by clinical, histological, and molecular assays. During CXL, riboflavin was instilled over the corneal and limbal surface every two min in group 1 rabbits (riboflavin without ring), and group 2 rabbits received riboflavin using a retention ring to avoid the limbus (riboflavin within ring). (b) Photographs of CXL procedure in the group 2 (riboflavin within ring). After marking and scraping the central 9.0 mm corneal epithelium, a retention ring was applied and riboflavin filled within a ring. (c) On Day 1, corneal epithelial healing was examined with 3% lissamine green dye staining and quantitated by a ratio of epithelial defect area to the total corneal area. (d) Hematoxylin-eosin staining. Original magnification ×200. The central corneal thickness was measured on stained slides. Data are presented as the mean ± SD, and a dot represents a single animal. ns: not significant.

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