Optimal Concentrations of hEGF for Epithelial and Endothelial Healing in Corneal Alkali Wounds: An Organ Cultured Study

ABSTRACT

Optimal concentrations of hEGF for epithelial and endothelial healing after alkali-injury were determined in an organ cultured system. By using a 5.5 mmround filter paper, corneal alkali wounds (1N NaOH, 60sec.) were induced in the rabbit eyes and then the whole cornea with 1 mmscleral rim were excised.The excised corneas were immersed in the Eagle`s minimum essential medium supplemented with 5% Dextran, 1%antibiotics and different concentrations of hEGF (DaeWoong Pharma.Co.Ltd. Seoul, Korea), i.e., O (control), 0.01, 0.1, 1.0, 10, 100ng/ml. After tryphan blue staining, morphometric analysis was performed at 1, 2, 3, 4 and 6 days time periods. The healing rates were calculated by using an image analysis system. After 7 days, the corneas were processed for an immunohistochemical observation of proliferating cell nuclear antigen (PCNA) positive cells in the re-surfaced epithelium. Epithelial re-surfacing was significantly enhanced by the hEGF treatment at a concentration of 1.0ng/ml. The thickness of regenerated epithelium appeared to be increased in a dose-dependent man-ner. The rate of endothelial healing was increased at the concentration of 100ng/ml. The results indicate that epithelial healing was stimulated at about 100 times lower concentration of hEGF than endothelial healing.