Experimental Treatment Of Alkali-induced Corneal Burns In Rabbit Eyes By Riboflavin-UVA Collagen Crosslinking And Drugs

Background Severe ocular alkali burns can cause corneal melting or even perforation,which is caused by the activation of corneal collagenase,which leads to the melting of collagen fibers.It is determined that riboflavin-ultraviolet A(UVA)induced collagen crosslinking is able to increase resistance of cornea against enzymatic degestion.However,whether it can be used for the treatment of corneal alkali burn has not been verified.Objective This study aimed to evaluate the efficaty of riboflavin-UVA induced collagen crosslinking combined with drugs on alkali-induced corneal burns in rabbits.Methods The left corneas of 40 rabbits were burned using a 1N solution of NaOH and the rabbits were then randomly divided into 4 groups:the model group,drugs treatment group,riboflavin-UVA corneal crosslinking group and drugs+crosslinking group.Riboflavin-UVA crosslinking was appied on the eyes of the riboflavin-UVA corneal crosslinking group and drugs+crosslinking group,and drugs were topically used on the eyes of the drugs treatment group and drugs+crosslinking group.The slit-lamp microscopy was performed every day after the operation.The corneal epithelial healing times were recorded,and the opacity scores was recorded at 3 months after operation.laser confocal microscopy was performed at 1 month after operation.the number of inflammatory cells in images was measured by Image J software.Corneal histopathology was performed after treatment for 3 months.Results The corneal epithelial healing time in the model group,drug group,cross-linking group and combination group were(32.9±5.8)days,(12.8±2.3)days,(25.9±3.2)days,and(10.7±2.5)days respectively,showing a significant difference among them(F=67.647,P=0.000).The corneal turbidity score of combination treatment group was lowest among the 4 groups,followed by the drug group,and the model group was the heaviest(F=6.446,P=0.001).the number of inflammatory cells in the model group of,drug group,cross-linking group and combination treatment group were(162.6±33.3),(46.0±21.3),(87.9±7.5)and(8.3±6.5)respectively in single confocal microscopy field of vision(400 um × 400 um).The difference among the 4 groups was statistically significant(?2=36.040,P=0.000).The corneal collagen fibers in the combination treatment group were the thickest and densely arranged,followed by cross-linking group.Conclusion The therapeutic effect of drug combined cross-linking in treating corneal alkali burn in rabbits is better than that of simple drug therapy or simple corneal collagen cross-linking.