Methods: These experimental Apo E-/- rats were separated into three groups. Group 1 (control group; n=6) rats were fed 0.5 cc/day olive oil, group 2 rats (n=4) were treated with 10 mg/kg/day cyclosporin in a 0.5 cc olive oil diet for four weeks and group 3 rats (n=5) were treated with 0.05 mg/kg/day tacrolimus in a 0.5 cc olive oil diet for four weeks. At the end of the 4th week, morphological analyses were made with light microscope hematoxylin-eosine x100 and x400. Levels of total cholesterol, HDL cholesterol and triglycerides in these three groups were compared in blood samples obtained from the aorta of the rats.

Results: There was no statistical difference with respect to total cholesterol and HDL cholesterol levels between the groups. Triglyceride level was considerably higher in cyclosporin and tacrolimus group than in control group, but there was no statistical difference in both cyclosporin and tacrolimus groups. In the morphological analysis with light microscope, there was no difference with respect to widening, thickening, intima-media proportion, aterom plaque morphology, endothelial desquamation, deposition of sub-endothelial lipid, degeneration in elastic ligaments of media layers, abnormalities in endothelial cell composition in the intima and media layers of the common carotid artery. Partial intimal thickness was detected in one of the cyclosporin group sample.

Conclusion: There was intimal thickening in one of the subjects in cyclosporin group, while there was no significant difference in cholesterol level. This suggests that cyclosporin may potentiate atherosclerosis by stimulation of vascular smooth muscle cell proliferation independent of its hyperlipidemic effect.