Changes in Bruch's Membrane in Experimental Hypercholesteremia in Rats

Abstract Purpose: We investigated the effect of high-cholesterol diet for aging changes in Bruch's membrane of rats. Methods: After feeding a 4% cholesterol diet for 15 weeks to three young rats 3 months old and four rats aged 23 months old, we observed the morphological changes of Bruch's membrane by electron microscopy, and made a comparison with rats fed an ordinary diet. Results: In one young rat fed a high-cholesterol diet, the endothelial basement membrane of the choriocapillaris formed multiple folds separated from the plasma membrane of the endothelium and showed lamellar thickening and cracking in some areas. The elastic fiber layer in Bruch's membrane disappeared partly and some new microfibrils appeared. In one aged rat fed a high-cholesterol diet, the endothelial basement membrane of the choriocapillaries showed more lamelar thickening with lumps in some parts. Compared with the rats fed an ordinary diet, rats fed a high-cholesterol diet showed thickening of the basement membrane and the changes were more severe. Conclusions: Our data indicated that high-cholesterol diet might promote age-related changes of Bruch's membrane.