Iris vasculopathy in galactose-fed rats

Increased iris vessel permeability observed in diabetics has also been repo rted to occur in diabetic animals and galactose-fed rats. The potential rol e of aldose reductase in the induction of iris vessel changes has been inve stigated in rats fed a 50%, galactose diet with/without the aldose reductas e inhibitors AL 1576, sorbinil or ponalrestat for 7 to 18 months. Compared to normal control rats, long-term galactose-fed rats display a breakdown of the blood-aqueous barrier due to iris vessel changes that include focal st raightening, dilation, constriction, increased permeability, ischemia and n ew vessel proliferation. The onset and progression of these iridal vessel c hanges were prevented by the aldose reductase inhibitors AL 1576 and sorbin il, and reduced by Ponalrestat, Computerized analyses of lumen areas of iri s vessels indicated an 18-fold decrease in the vascular area near the pupil lary boarder in untreated galactose-fed rats compared with age-matched cont rols and galactose-fed rats treated with aldose reductase inhibitors, These observations linking iris vessel changes with galactose-feeding, coupled w ith the fact that aldose reductase inhibitors also prevent these changes, s trongly suggest a link between the sorbitol pathway and the appearance and progression of iris vessel changes. (C) 1999 Academic Press.