Abstract
Abstract: :
Purpose: Hypercholesterolemia reportedly increases leukocyte-endothelium adhesion in the retinal microcirculation. This study was designed to investigate the effect of nitric oxide (NO) donative action of nipradilol, an α1, ß-blocker, on augmented leukocyte-endothelium interaction in hypercholesterolemic rats. Methods: Male Long-Evans rats were divided into 4 groups. Groups A-C were fed with high cholesterol (5%) diet for 8 weeks. Group A received one eyedrop of nipradilol (1%) twice daily during a period of high cholesterol diet. Group B received one eyedrop each of timolol (0.5%) and bunazosin (0.125%) twice daily during the same period. Group C had vehicle instillation only (Control). Group D were fed with normal diet (cholesterol; 0.1%) and had vehicle instillation. The leukocyte velocity traveling in the retinal capillaries and the number of leukocytes trapped in the retinal microcirculation were evaluated with acridine orange digital fluorography. Results: The number of trapped leukocytes 30 minutes after dye injection was significantly greater in hypercholetsterolemic rats (Groups A, B and C) than in Group D (15.8±1.2, 19.7±0.8, 20.2±0.6 and 12.8±0.3 cells/mm2, respectively, p<0.001). The number in Group A was significantly lower than that of Group C (p<0.01), however, there were no significant differences in the number of trapped leukocytes between Group B and C. The leukocyte velocities in the capillaries showed no significant differences among all groups. Conclusion: The present study suggests that a NO donative action of topical nipradilol may reduce endothelial cell damage by decreasing leukocyte-endothelium interaction in hypercholesterolemia.
Keywords: 390 drug toxicity/drug effects • 491 nitric oxide • 554 retina