Neuroprotective Effects of Memantine in the Retina of Glaucomatous Rats: An Electron Microscopic Study

PURPOSE: In this experimental study, the effects of systemic memantine administration on the retinal ultrastructure of experimentally induced glaucomatous rats were investigated. METHODS: Twenty-four Wistar albino rats were included in this study. Glaucoma was induced by injecting sodium hyaluronate into the anterior chamber of the rats for a period of three weeks. As a control, 8 rats were sham treated (Group C). Glaucoma induced animals were divided into two groups; Group M (n = 8) received a single daily dose of 10 mg/kg memantine, and Group G received the same volume of saline (n = 8), via intraperitoneal route for a period of six weeks, starting with the induction of glaucoma. Then, all rats were sacrificed and the retinas were prepared for electron microscopic examination. Electron microscopic damage findings were graded between 0 and 4 and mean damage scores for each cell or layer was calculated for each group. Statistical comparison was made between group G and group M. RESULTS: Including the photoreceptor cells, marked ultrastructural changes were observed in the retinas of the animals in group G. The ultrastructural changes in group M were modest and there was no significant cell death. Statistical findings indicated these results. CONCLUSION: Results of the present study suggest that memantine treatment, when started in the early phase of glaucomatous process, may help to preserve the retinal ultrastructure and thus prevent neuronal injury in experimentally induced glaucoma.