Analysis of glycosaminoglycans in rabbit cornea after excimer laser keratectomy

Background/aims-The biochemical basis for the development of subepithelial opacity of the cornea after excimer laser keratectomy has yet to be fully d efined. The aim of this study was to evaluate the alterations of glycosamin oglycans (GAGs) after excimer laser keratectomy. Methods-Rabbit corneas were harvested on days 5, 10, 20, and 30 after excim er laser photoablation. The amount of main disaccharide units was determine d by high performance liquid chromatography (HPLC). In addition, immunohist ochemical studies were performed an corneal sections 20 days after the abla tion, Results-The concentrations of Delta Di-0S at 5 and 10 days were significant ly lower than before the ablation. Delta Di-6S showed a significant increas e 5 days after the ablation but Delta Di-4S did not show any significant ch ange. There was a significant increase in Delta Di-HA at 20 and 30 days aft er ablation. In immunohistochemistry, the positive staining for Delta Di-6S and hyaluronic acid was observed in the subepithelial region. These immuno histochemical results were well correlated with the HPLC findings. Conclusions-The increase in chondroitin-6 sulphate and hyaluronic acid may be related to corneal subepithelial opacity after excimer laser keratectomy .