Purpose:
Erythropoietin (EPO) has been shown to have neuroprotectiveeffects in several animal models. This pilot study assessedthe safety of a single intravitreal injection of varying dosesof EPO on retinal function in rats.
Methods:
Twenty–four Sprague–Dawley rats were randomlydivided into one of 7 groups: control, sham injection, vehicleinjection, and EPO injections of 50ng, 100ng, 250ng, and 625ng (N=3–4 per group). Only the right eyes were treatedin each animal. Scotopic and photopic full–field ERGswere taken from both eyes simultaneously one day prior to theintravitreal injections (baseline), then 3, 7, 14, and 21 daysafter the injections. After dark adaptation, scotopic maximalresponse ERGs were obtained using (3 cd–s/m2) on a darkbackground. Photopic ERGs were recorded using the (3 cd–s/m2)on a white background (30 cd/m2). The amplitude and latencyof each component were analyzed. The contralateral eye was usedto correct for inter–experimental variability. Group designationswere unmasked after all ERGs were performed. Statistical analysiswas carried out using Two–way ANOVA.
Results:
In all groups and at all time points, scotopic and photopicresponses showed no statistically significant difference inboth amplitude and latency compared to baseline and controlvalues (except for photopic b–wave amplitude of vehicleinjection, day 14). The scotopic a–and b–wave readingsare shown below.
Conclusions:
A single intravitreal injection of EPO (at dosesup to 625 ng) does not appear to affect retinal function inrats as assessed by ERG response. These results warrant furtherinvestigation to assess fully the ocular safety of this potentialneuroprotective agent.
Keywords: drug toxicity/drug effects • electroretinography: non-clinical • neuroprotection