STEREOLOGICAL ESTIMATION OF WEIBEL-PALADE BODIES IN THE RETINAL VASCULATURE OF NORMAL AND DIABETIC DOGS

The absolute volume of Weibel-Palade (WP) bodies, the storage organell es of von Willebrand factor (vWF), was estimated by a stereological me thod in a known volume of central retina from normal and 5-year diabet ic dogs. The results showed that the volume of WP bodies present in th e endothelium of the retinal vasculature varies with blood vessel type and in diabetes. In both diabetic and normal dogs the endothelium of the retinal veins contained a higher volume of WP bodies than that of the retinal arteries. In dogs which had been diabetic for a duration o f 5 years the volume of WP bodies present in the endothelium of retina l veins was significantly greater than in the endothelium of veins fro m the control animals. However, there was no significant difference in the volume of WP bodies present in the endothelium of retinal arterie s or capillaries between the two groups of animals.