Crosslinking-Induced Corneal Endothelium Dysfunction and Its Protection by Topical Ripasudil Treatment

PURPOSE: To investigate the changes of corneal endothelium under different crosslinking conditions and the protective effect of ripasudil. METHODS: Corneal crosslinking groups were infiltrated with riboflavin and subsequently irradiated with 0.54 J/cm(2) or 1.08 J/cm(2) UVA, while noncrosslinking groups included neither UVA nor riboflavin treatment, only 1.08 J/cm(2) UVA and only riboflavin treatment. Corneal opacity, variations in corneal endothelial cells, and corneal thickness of all groups were observed by slit lamp, in vivo confocal microscopy, and optical coherence tomography. Immunofluorescence staining and scanning electron microscopy were performed to evaluate changes in the structure and function of the corneal endothelium. The mice that received a corneal crosslinking dose of 1.08 J/cm(2) were instilled with ripasudil to explore its protective effect on the corneal endothelium. RESULTS: Treatment with UVA and riboflavin caused an increase in corneal opacity and corneal thickness and decreased endothelial cell density. Furthermore, treatment with UVA and riboflavin caused endothelial cell DNA damage and destroyed the tight junction and pump function of the endothelium, while riboflavin or the same dose of UVA alone did not affect the endothelium. Ripasudil reduced DNA damage in endothelial cells, increased the density of cells, and protected the endothelium's integrity and function. CONCLUSION: Riboflavin combined with UVA can damage the corneal endothelium's normal functioning. The corneal endothelium's wound healing is dose-dependent, and the ROCK inhibitor ripasudil maintains the endothelium's pump and barrier functions.