Abstract
Abstract: :
Purpose: Brimonidine has been shown to have neuroprotective effect on retinal ganglion cells following calibrated injury on the optic nerve (Yoles et. al, IOVS 40:65, 1999). This study was done to evaluate the neuroprotective effect of different formulations of topically applied brimonidine in the calibrated optic nerve injury model. Methods: Calibrated injury was applied to the optic nerve about 2 to4 mm from the globe, as described previously (Yoles et al, IOVS 40:65, 1999). Brimonidine tartarate formulations, in benzalkonium chloride (BAK) at 0.2% or in purite formulation at 0.15% were applied topically immediately after optic nerve injury. Twelve days later ganglion cell survival was evaluated by counting ganglion cells that were retrograde labeled with rhodamine labeled dextran. Results: Topical application of brimonidine of both formulations was effective in increasing ganglion cell survival. Brimonidine tartarate (0.15%) in purite increased ganglion cell survival by 1.6 fold and brimonidine in BAK (0.2%) increased survival by 1.8 fold. Ganglion cell survival by both formulations was significantly higher than those treated with vehicle. Cell survival by brimonidine tartarate in purite and BAK were not significantly different from each other. Conclusion: Topically applied brimonidine was protective to ganglion cells after calibrated optic nerve injury. The effects of brimonidine tartarate in BAK and in purite were equivalent in increasing ganglion cell survival.
Keywords: 415 ganglion cells • 489 neuroprotection • 554 retina