Effect of memantine: A NMDA receptor blocker, on ethambutol-induced retinal injury

In the ETM group, the neural retina became significantly thinner (p < 0.05) and the ganglion cell layer (GCL) was the main layer affected in the form of a significant decrease (p < 0.001) in its cellularity, along with an obvious increase in Bcl-2 and GFAP expression as well as caspase-3 and oxidative stress markers level compared with other groups. On the other hand, on combining MEM with ETM, the retinal thickness, NFL appearance and GCL cellularity returned to amounts nearly similar to the control group coupled with a significant decrease (p < 0.05) in the detected caspase-3, Bcl-2 levels and minimal GFAP expression. Therefore, memantine could be an effective neuroprotective agent in ETM-induced retinal injury by a mechanism that may involve correction of the pro/anti-apoptotic pathways and normalization of the oxidative and Müller cell stress responses.