Effect of antiplatelet drug therapy on the retinal vascular pattern in experimental diabetes mellitus.

We performed a study to evaluate the effect of acetylsalicylic acid (ASA) plus dipyridamole on the retinal vascular pattern over 3 months in rats with experimental diabetes mellitus. Rats treated with ASA alone showed a continuous vascular bed and less tortuous vessels than untreated diabetic rats. Rats treated with ASA plus dipyridamole showed a continuous vascular bed, scarce tortuous vessels and vascular diameters similar to those in nondiabetic control rats. The findings were related to aortic prostacyclin production: treatment with ASA alone produced a reduction in prostacyclin production, whereas treatment with ASA plus dipyridamole resulted in normal prostacyclin production. ASA alone or with dipyridamole inhibited collagen-induced aggregation in whole blood by 57% compared with the untreated diabetic rats.