RETINAL VESSEL CHANGES IN GALACTOSE-FED DOGS

Background: Retinal lesions similar to those in human early-stage diab etic retinopathy have been reported to occur in dogs fed galactose for long periods. Investigations of retinal changes, however, have been l imited to studies of the intact retinal vasculature isolated by trypsi n digestion. Objective: To document the onset and progression of retin al lesions in galactose-fed dogs by the common clinical techniques of fundus color photography and fluorescein angiography. Methods: Fourtee n 6-month-old male beagles made aphakic in 1 eye were divided into a c ontrol group (4 dogs), receiving a diet containing 30% cellulose, and a galactosemic group (10 dogs), receiving a diet containing 30% galact ose. The progression of retinal changes in these dogs was periodically monitored by color fundus photography and fluorescein angiography. Re sults: Dogs fed a 30% galactose diet for 28 to 41 months were observed by fluorescein angiography and color fundus photography to develop, i n order of frequency, microaneurysms, retinal hemorrhages, intraretina l microvascular abnormalities, retinal nonperfused areas, and varicose and serpiginous veins. These findings are similar to the early clinic al retinal changes observed in humans with diabetes. Conclusion: These results confirm that galactosemic dogs are an appropriate and suitabl e animal model for investigating human diabetic retinopathy.