Effect of aldose reductase inhibitor on corneal epithelial barrier function in galactose-fed dogs

The effect of concomitant administration of galactose and the aldose reductase inhibitor(ARI) Epalrestat (Kinedak) on corneal barrier function was examined in dogs. Six-month-old male beagles were rendered aphakic in one eye and then divided into four groups as follows: 1) a control group fed on 30% cellulose, 2) a galactosemic group fed on 30% galactose, 3) a 30% galactose-fed group treated with low dose (20 mg/kg) ARI and 4) a 30% galactose-fed group treated with high dose (50 mg/kg) ARI. Forty-one months after the start of these diets, corneal autofluorescence and the corneal barrier function were measured in each dog using anterior fluorophotometry (FL-500). When barrier function was analyzed in non-operated eyes, fluorescence data were significantly higher in the galactosemic group compared to the control group. In non-operated eyes, fluorescent data in high-dose ARI treated group were significantly lower than those in the galactosemic group. However, in operated eyes, no significant difference was observed between the galactosemic group and the ARI treated groups. Similar trends were observed when corneal autofluorescence of each group was compared. Long-term galactose feeding appeared to damage corneal epithelial barrier function. This damage was not observed in the high-dose ARI treated group suggesting that this damage may be linked to the polyol pathway.