A pilot study of genipin cross-linking effects on bullous keratopathy in rabbits

AIM:To evaluate the effects of genipin cross-linking on bullous keratopathy in rabbits.METHODS:Nine female New Zealand white rabbits with bullous keratopathy were used as an experimental model.They were randomized into three groups.Corneas in Group A (treatment group,n=3) were immersed in 0.25% genipin at 24℃ for 40min;those in Group B (control group,n=3) were immersed in 0.9% sodium chloride solution at 24℃ for 40min;and those in Group C (blank control group,n=3) received no treatment.Follow-up examinations were performed within 2wk after treatment,including slit-lamp microscopy,central corneal thickness (CCT),evaluations of body weight and stress responses,histopathological analyses,and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) for detecting stromal cell apoptosis.RESULTS:Compared to Groups B and C,remission of corneal edema,corneal healing,disappearance of epithelial bullae,a significant decrease in CCT (P<0.05),and a significant increase in body weight (P<0.05) were found in Group A.Animals in Group A became more active and showed less aggression and violent resistance behavior.More regular and dense arrangement of collagen fibers in the corneal stroma and formation of blue strips of cross-linking products were observed in Group A.Cell apoptosis occasionally occurred in the corneal stroma of Group A,while no cell apoptosis was observed in Groups B and C.CONCLUSION:Genipin cross-linking treatment for bullous keratopathy in rabbits results in remission of corneal edema and relief of pain.We hypothesize that genipin cross-linking strengthens collagen fibers in corneal stroma to avoid the formation of corneal edema and bullae.