Statins Reduce Choroidal Ischemia in Hyperchoresterolemic Rabbits

Abstract

Purpose: : To evaluate the choroidal ultrastructural changes in hypercholesterolemic rabbits after treatment with statins.

Methods: : New Zealand rabbits were divided into four groups: Control (G1; n=10), fed a standard diet for 8 months; Hypercholesterolemic (G2, n=10), fed a 0.5% cholesterol-enriched diet for 8 months; Fluvastatin (G3, n=10), fed a 0.5% cholesterol-enriched diet for 8 months along with fluvastatin; Simvastatin (G4, n=10), fed a 0.5% cholesterol-enriched diet for 8 months along with simvastatin. Eyes were processed for transmission electron microscopy.

Results: : Hypercholesterolemic rabbits (G2) had a buildup of lipids at the suprachoroidea which compressed the vascular layers. G3 and G4 rabbits presented a substantial decrease in the number of suprachoroidal foam cells and lipids in the vascular layers, but more fibroblasts and collagen fibers. The lumen of the vessels at the choriocapillaris and at the large- and medium-sized vessel layer were dilated in animals treated with statins in comparison with G2 rabbits, where the capillary lumen was reduced to the point of collapse in some instances, due both to compression and to hypertrophy of endothelial and vascular smooth muscle cells. The normal appearance of endothelial cells in G3 and G4 rabbits contrasted with the endothelial necrosis observed in G2. Bruch’s membrane contained less lipids and more collagen in G3 and G4 than in G2.

Conclusions: : Treatment with statins reduces the buildup of lipids and the number of macrophages in the choroid. In addition, it preserves the endothelial cells and dilates the vascular lumens of choroidal vessels.

Keywords: optic nerve • retina • ischemia