Effect of Carteolol on Leukocyte Dynamics in Retinal Microcirculation of Hypercholesterolemic Rats

Abstract

Abstract: : Purpose: Hyperchoresterolemia is an important risk factor of atherosclerosis and cardiovascular disease. We have previously demonstrated that hypercholesterolemia induces leukocyte entrapment in the retinal microcirculation. In the present study, we investigated effect of carteolol, nonselective beta-blocker which can increase the optic nerve head blood flow, on leukocyte-endothelial cell interaction in the retinal microcirculation of hypercholesterolemic rats. Methods: Male Brown-Norway rats weighing approximately 200g were fed with high cholesterol (5%) diet for 8 weeks. They were divided into two groups. Group A had no treatment. Group B received carteolol (100µg/kg) intravenously 30 minutes before acridine orange digital fluorography. We evaluated the leukocyte velocity circulating in the retinal capillaries, retinal vessel diameters and the number of leukocytes accumulated in the retinal microcirculation. Results: Plasma cholesterol level and mean arterial blood pressure showed no significant differences between two groups. The number of accumulated leukocytes 30 minutes after dye injection was significantly lower in group B than in group A (12±2 and 30±3 cells/min², respectively, P<0.01). Neither leukocyte velocity nor retinal vessel diameter exhibited significant differences between two groups. Rolling leukocytes in the retinal vein were not observed in both groups. Conclusions: Carteolol may have a therapeutic effect on retinal microvascular dysfunction in hypercholesterolemia by preventing leukocyte entrapment.

Keywords: retina