Effects of erythropoietin on neuroprotection in an experimental glaucoma model

PURPOSE: Glaucoma is a progressive, irreversible optic neuropathy that is the leading cause of blindness worldwide. In our study, we aimed to show the neuroprotective effect of erythropoietin (EPO) on glaucoma.
METHODS: Twelve male and 12 female albino Wistar rats (6 weeks old; 220±40 grams) from Aydin Adnan Menderes University Experimental Animal Center were used. All animals were housed in a fixed room on a 12/12 h light/dark cycle per day, with food and water provided ad libitum. Rats were divided into four groups as control and glaucoma groups, subconjunctival EPO and topical EPO groups. At the end of the 6th week, the right eyes were enucleated and total retinal thickness, ganglion cell complex (GCC), inner plexiform layer (IPL), and ganglion cell layer (GCL) thickness measurements were determined. Tis-sue samples stained with HE were examined under a light microscope and photographed. Retinal layer thickness measure-ments were determined for each eye using the ImageJ program (NIH, USA). The neuroprotective effect of EPO on glaucoma was evaluated by retinal layer thickness measurements.
RESULTS: GCL, IPL, retinal thickness, and GCC thickness were observed the least in the glaucoma group and the most in the control group. There was no significant difference between EPO administration routes (p>0.05). Cell layer thicknesses in each group were confirmed by immunohistochemical staining, and apoptotic cells were not detected by bax or bcl-2 staining.
CONCLUSION: The structural contribution of topical and subconjunctival applications of EPO to retinal layers has been demonstrated, and the study needs to be repeated in larger series.