Intravitreal injection of soluble erythropoietin receptor exacerbates photoreceptor cell apoptosis in a rat model of retinal detachment.
OBJECTIVE
To evaluate the effects of intravitreal injection of soluble erythropoietin (EPO) receptor (sEPOR) on photoreceptor cell apoptosis in an animal model of retinal detachment (RD).


METHODS
Various dosages of sEPOR (2, 20, or 200 ng) were injected into the vitreous cavities of normal rats. Three days after injection, retinal function was measured by flash electroretinography (ERG). On day 7, histopathology and retinal morphology were examined by light and transmission electron microscopy (TEM), respectively. Rat models of RD were successfully established by injection of 1.4% sodium hyaluronate into the subretinal space, followed by immediate injection of phosphate-buffered saline (PBS) or sEPOR into the vitreous cavity. On day 3, photoreceptor cell apoptosis was evaluated using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), and caspase-3 activity assayed by Western blotting and immunofluorescence. Light microscopic examination of retinal histopathology was used to determine the thickness of the outer nuclear layer (ONL) 14 days after establishment of RD.


RESULTS
There were no significant differences in the latency and amplitude of maximal a, b and oscillatory potential (OP) wave responses by flash ERG before or 3 days after sEPOR injection (p > 0.05). Retinal tissues showed no obvious pathological changes by either light or transmission electron microscopy. Both Western blotting and immunofluorescence indicated consistent sEPOR enhanced caspase-3 activation aggravated apoptosis of photoreceptor cells in RD rat retinas. On day 14, RD ONLs were thinner, according to increasing dosages of sEPOR.


CONCLUSIONS
Intravitreal injection of sEPOR exacerbates photoreceptor cell apoptosis in RD models via activation of caspase-3.
Department of Ophthalmology, Clinical Medicine School, Yangzhou University, Subei People's Hospital of Jiangsu Province, No. 98 Nantong West Road, Yangzhou, Jiangsu, China.
Fang
F
Chen
Zhenggao
Z
Xie
Xingwei
X
Wu
Wei
W
Du
Jian
J
Wang
Jun
J
Zhu
Heqing
H
Ji
Yakun
Y
Wang
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D004195:Disease Models, Animal; D004596:Electroretinography; D019084:Fluorescent Antibody Technique, Indirect; D020287:In Situ Nick-End Labeling; D058449:Intravitreal Injections; D008297:Male; D010775:Photic Stimulation; D020419:Photoreceptor Cells, Vertebrate / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017467:Receptors, Erythropoietin / Q000008:administration & dosage*; D012163:Retinal Detachment / Q000201:enzymology / Q000473:pathology*
D017467:Receptors, Erythropoietin; D053148:Caspase 3