Effect of aldose reductase inhibitor on fluorescein angiographic lesions in galactose-fed dogs

Purpose. To evaluate the effects of aldose reductase inhibitor on the diabetic-like retinopathy induced by galactose feeding in dogs. Methods. At 3 months of age, 20 male beagle dogs were rendered aphakic bilaterally. At 9 months of age, 12 dogs were fed a 30% galactose diet (control group) and 8 were fed a 30% galactose diet including an aldose reductase inhibitor Eisai M79175 (treatment group). After 34 months of galactose feeding, the treated dogs were placed on a normal diet and the aldose reductase inhibitor was discontinued. Stereoscopic fundus photographs and fluorescein were performed in a standardized fashion at baseline and at 6 month intervals. The photographic data, graded by a masked reader, was assessed for the development of retinal hemorrhages, the degree of retinal nonperfusion and the presence of retinal neovascularization. Results. Retinal hemorrhages first appeared at 24 months and 48 months in the control group and the treatment group, respectively. By 60 months of follow-up, 100% of the controls developed nonperfusion and only 20% of the treated group developed nonperfusion. The rates of progression of nonperfusion and the development of neovascularization were significantly higher in the control group than in the treated group (p<0.001). Conclusions. Aldose reductase inhibitor is effective in significantly delaying the onset of diabetic-like retinopathy in dogs on galactose feed.