Abstract
Abstract: :
Purpose: To investigate the protective effect of theanine, γ-glutamylethylamide, against neurotoxicity of retinal ganglion cells of rats with chronic moderately elevated intraocular pressure (IOP). Methods: Chronic, moderately elevated IOP was produced unilaterally in rats by cautery of three episcleral vessels. Secondary degeneration was measured with and without 1 mM theanine for 5 months. At 5 months, retinal ganglion cells were labeled with a fast blue tracer applied to both superior colliculi. Densities of surviving retinal ganglion cells were estimated by counting fast blue labeled cells in whole mounted retinas. Results: IOP was elevated in all eyes after receiving three-vessel cautery compared with control eyes. When compared with their contralateral control eyes with normal IOP, retinal ganglion cell loss in eyes with chronic, moderately elevated IOP was 30.9 ± 2.6% (n = 5) at 5 months in untreated animals and 12.1 ± 1.7% (n =5 ) at 5 months in treated animals with theanine (p < 0.05). Conclusions: Pretreatment and early posttreatment with theanine is an effective neuroprotectant in a rat model of chronic glaucoma.
Keywords: ganglion cells • neuroprotection • pharmacology