Retinal vascular changes in rats with inherited hypercholesterolemia--corrosion cast demonstration.

Purpose. To demonstrate specific hypercholesterolemic changes in the retinal vascular architecture. Methods. Corrosion casts of 12- to 18-month-old rats with inherited hypercholesterolemia (RICO) and of control Wistar Kyoto (WKy) rats were examined with a scanning electron microscope (SEM). The diameters of the retinal arteries, veins and capillaries were measured in photographs with a caliber micrometer. The capillary branches were counted in the micrographs with the use of Adobe Photoshop. The retinal capillaries were examined by transmission electron microscopy (TEM). Results. SEM examination of the vascular casts of 15-month-old RICO rats showed slight tortuosity of large vessels at the posterior pole of the retina. The precapillary arterioles branching from the major artery were longer and straighter than normal. Retinal capillary changes such as caliber irregularity and narrowing in the capillary network were more severe in 18-month-old RICO rats. The most prominent finding was marked straightening ...