Protective Effects On Corneal Endothelium During Intracameral Irrigation Using N-(2)-L-alanyl-L-Glutamine

Purpose:Ocular trauma,cataract surgery,diabetes and endothelial corneal dystrophy can contribute to endothelial decompensation.The endothelial keratoplasty is the only treatment for endothelial decompensation to restore vision.The present study was to investigate the protective effect of N-(2)-L-alanyl-L-Glutamine(Ala-Gln)on corneal endothelium to provide a new method in the prevention of endothelial decompensation.Methods:The acute intraocular hypertension was induced in mice to establish the corneal endothelium injury model.Mice in the control or experimental groups were irrigated with Ringer’s lactate injection without or with 5mmol/L Ala-Gln for 1 hour,respectively.The intraocular pressure was 44 ± 3.5 mmHg during intracameral irrigation.The morphology and density of the corneal endothelial cells(CECs)were assessed using in vivo confocal microscopy(IVCM)at different time points after irrigation(day 0,day 2,and day 10).Corneal thickness was determined by optical coherence tomography(OCT).The integrity of tight junction in the corneal endothelium was analyzed by scanning electron microscopy(SEM).The corneal endothelial barrier function and pump function was separately evaluated using the immunofluorescence staining of the filamentous actin(F-actin)and sodium-potassiumATPase.The morphology and activity of mitochondria in the endothelium were labeled and evaluated using the mitoTracker Red CMXRos(MTR).The ultrastructure of CECs was detected using Transmission electron microscopy(TEM).Results:IVCM results showed acute intraocular hypertension induced by intracameral irrigation severely destroyed the corneal endothelium,and the addition of Ala-Gln protected the corneal endothelial structure and density.The endothelial density in the experimental groups was significantly increased.The OCT analysis indicated that the treatment of Ala-Gln greatly promoted the recovery of the corneal edema.SEM results showed the treatment of Ala-Gln maintained the cell tight junction in corneal endothelium.The intracameral irrigation using Ala-Gln minimized the damage to the corneal endothelial barrier function and pump function caused by acute ocular hypertension.Compared with the control groups,the addition of Ala-Gln during intracameral irrigation enhanced the activity of mitochondria.Moreover,TEM showed the treatment of Ala-Gln obviously prevented the ultrastructural alterations induced by acute intraocular hypertension.Conclusion:This study suggests that the addition of Ala-Gln inhibits the disruption of the corneal endothelial barrier function induced by acute ocular hypertension and enhances the pump function in corneal endothelium,which may provide a new approach in the prevention of corneal endothelial damage.