Abstract
Abstract: :
Purpose:To investigate the structures of choroid and retina of hyperlipidemic model rat by electron microscope. Methods:As hyperlipidemic model rats RICO rats (18 months old, n = 5) were used, and as controls Wistar Kyoto rats (18 months old, n = 5) were used. They were given standard foods and aqueduct water. Room was illuminated for 12 hours a day. In the room temperature was set 21±2 degrees and humidity was set 55±5%. Under anesthesia with intraperitoneal pentobarbital the eyes were enucleated and cut into small pieces. Then they are fixed in 4% glutaraldehyde for 1 hour, washed in 0.05 M cacodylate buffer overnight, placed in Caulfield osmium fixative for 1 hour, dehydrated in a series of ethanols and embedded in Luveak 812. Ultrathin sections were cut and stained with uranyl acetate and lead citrate, and examined under transmission electron microscope. The differences between the structures of choroid and retina of RICO rat and those of Wistar Kyoto rat were investigated. Results:In the choroid of RICO rat the figures of capillary and artery were flat and their lumens were stenotic. And smooth muscle of choroidal artery thickened remarkably. The electron density of secondary lysosomes of retinal pigment epithelium was high. Although the number of cell layers of outer nuclear layer was normal, the number of synapses of outer plexiform layer was small. In outer plexiform layer the stenosis of lumen of capillary was also seen. In inner nuclear layer the numbers of bipolar cells, horizontal cells and amacrine cells were small, especially of horizontal cells. Conclusions:In choroid and retina of hyperlipidemic model rat not only injuries of the structures for blood circulation but also changes of the structures which participate in visual functions were seen. These facts suggest hypercholesterolemia give birth to failures of visual functions.
Keywords: microscopy: electron microscopy • pathology: experimental • retina