Abstract
Abstract: :
Purpose: The mean aqueous humor nitric oxide (NO) level was reported to be higher in glaucoma patients than in the cataract patients. The aim of this study was to investigate the effects of alpha 2-adrenoreceptor agonist, brimonidine, and prostaglandin analog, latanoprost, on the levels of NO in the aqueous humor and on blood-aqueous barrier in patients with cataract. Methods: The study comprised 60 consecutive patients who were treated electively for senil cataract. Topical phenylephrine 10% and cyclopentolate 1% were used 3 times to dilate the pupil before surgery. Then, the patients were randomly assigned to treatment with brimonidine tartrate 0.2%, latanoprost 0.005%, or plasebo. One drop of brimonidine, latanoprost or plasebo was instilled at 12 hours, 2 hours and 1 hour preoperatively. 100 µL aqueous humor was collected during paracenthesis prior to cataract surgery by phacoemulsification. As an indicator for NO, aqueous total nitrite levels (end-product of NO) were measured by Griess reaction. Aqueous protein concentration was measured as an index of blood-aqueous barrier integrity. The Mann-Whitney U test used for statistical analysis and p<0.05 was considered significant. Results: The mean age and sex in the groups were comparable. The mean aqueous NO levels in brimonidine treated eyes were significantly lower than that was in plasebo-treated eyes (p<0.05; 8.2±4.6 for brimonidine group, 12.2±6.5 for latanoprost group, and 13.7±6.6 for plasebo group. The mean protein concentration in brimonidine-treated eyes were significantly lower than in latanoprost-treated and plasebo-treated eyes (p<0.05; 7.4±3.5 for brimonidine group, 11.5±6.9 for latanoprost group, and 20.2±11.5 for plasebo group. Conclusions: The results of this study indicate that brimonidine tartrate 0.2% significantly reduced the NO levels in aqueous humor in cataract patients. While latanoprost 0.005% did not change blood-aqueous barrier, brimonidine tartrate 0.2% significantly reduced blood-aqueous permeability.
Keywords: drug toxicity/drug effects • ganglion cells • pharmacology