Stereological analysis of changes in the 3-dimensional structure of the retinal vasculature during diabetes
Department of Ophthalmology, Institute of Clinical Sciences, The Queen’s University of Belfast, Belfast, Northern Ireland, BT12 6BA
Department of Ophthalmology, Institute of Clinical Sciences, The Queen’s University of Belfast, Belfast, Northern Ireland, BT12 6BA
Department of Ophthalmology, Institute of Clinical Sciences, The Queen’s University of Belfast, Belfast, Northern Ireland, BT12 6BA
Abstract
This study generated quantitative estimates of changes in the 3-dimensional structure of the retinal vasculature during diabetes. Male Wistar rats were rendered diabetic with streptozotocin and sacrificed in groups of 6 animals after 6 months and l year duration of diabetes together with similar numbers of control rats. The eyes were enucleated and fixed for transmission electron microscopy. Using trephine blades, circular tissue blocks were cut from the central retina and embedded in resin. Estimates of the 3-dimensional structure of the retinal capillaries were produced using the modem stereological method of ‘vertical sections’ specifically adapted to generate estimates of volume and surface area of structures in vertical sections of retina. After 1 year of diabetes the volume and surface area of retinal capillary basement membrane had increased compared to both the corresponding controls and the 6 month diabetics (p ≤0.05). The volume of retinal capillaries also increased after l year of diabetes (p ≤0.05). The volume of capillary endothelium and pericytes was greater in the l year diabetics than in the 1 year controls or 6 month diabetics (p ≤0.05). The data produced by this study represents the first estimates of the 3-dimensional structure of the retinal vasculature and the changes which occur during the development of diabetes.