Intravitreal administration of erythropoietin and preservation of retinal ganglion cells in an experimental rat model of glaucoma.
OBJECTIVE
The aim of this pilot study was to evaluate the potential neuroprotective effect of an intravitreal injection of erythropoietin (EPO) on retinal ganglion cell (RGC) preservation in an episcleral vessel cautery-induced rat model of glaucoma.


METHODS
The animals were randomly assigned into an unoperated control group (n = 11) and three experimental groups: episcleral vessel cautery only (EVC: n = 4), episcleral vessel cautery with intravitreal normal saline injection (EVC-NS; n = 5), and episcleral vessel cautery with intravitreal EPO treatment (EVC-EPO; n = 9). The intravitreal injections were limited to 5 mul containing either normal saline alone or 200 ng of EPO in normal saline administered immediately after the cautery procedure. RGCs were labeled retrogradely by FluoroGold neuron tracer 5 to 7 days prior to the collection of eyes at day 21 and counted in whole flat-mounted retinas with fluorescence microscopy.


RESULTS
Compared to the RGC counts in retinal specimens from unoperated control rats (12,619 +/- 310), the corresponding RGC counts were significantly decreased in both the EVC (9116 +/- 273; p < 0.005) and EVC-NS (9489 +/- 293; p < 0.005) groups but not significantly decreased in the EVC-EPO (11,212 +/- 414; p = 0.051) treated retinas.


CONCLUSIONS
A single intravitreal 200 ng dose of EPO appears to have a protective effect on RGC viability in an in vivo rat model of glaucoma. Further experimental studies are needed to confirm these preliminary results and to optimize the appropriate dose and frequency of EPO delivery in animal models of glaucoma.
Tsai
James C
JC
Brown Glaucoma Research Laboratory, Department of Ophthalmology, Columbia University College of Physicians and Surgeons, New York, USA. jct2002@columbia.edu
Wu
Li
L
Worgul
Basil
B
Forbes
Max
M
Cao
Jingtai
J
D000818:Animals; D002452:Cell Count; D002470:Cell Survival / Q000187:drug effects; D004921:Erythropoietin / Q000008:administration & dosage* / Q000494:pharmacology; D005901:Glaucoma / Q000473:pathology* / Q000503:physiopathology*; D007267:Injections; D007429:Intraocular Pressure; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins; D012165:Retinal Ganglion Cells / Q000187:drug effects* / Q000473:pathology; D012171:Retinal Vessels / Q000187:drug effects; D014822:Vitreous Body
D011994:Recombinant Proteins; D004921:Erythropoietin