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April 1980

A Permeability Defect of the Retinal Pigment Epithelium: Occurrence in Early Streptozocin Diabetes

Author Affiliations

From the Department of Ophthalmology, Scheie Eye Institute and the George S. Cox Medical Research Institute, University of Pennsylvania School of Medicine, Philadelphia. Dr Kirber is now with the Department of Ophthalmology, Washington University School of Medicine, St Louis.

Arch Ophthalmol. 1980;98(4):725-728. doi:10.1001/archopht.1980.01020030719015

• The permeability of the blood-retina barrier was tested in rats with early streptozocin-induced diabetes. Two different tracer substances were used: fluorescein sodium and horseradish peroxidase (HRP). After intravenous administration, the ocular distribution of fluorescein was studied by fluorescence microscopy of freeze-dried tissue. A permeability defect of the pigment epithelium to fluorescein was present in one half of the rats four weeks after induction of diabetes. The dye entered the pigment epithelial cells but could not be detected among the photoreceptors. The only dye visible in neural retina was within the retinal blood vessels. For HRP, no fault whatsoever in the blood retina barrier was found: there was no increase of vesicular uptake by the pigment epithelial cells; the tight junctions between pigment epithelial cells were intact as were those between the endothelial cells of retinal blood vessels.