[Erythropoietin administration protects retina against light-induced retinal degeneration].
OBJECTIVE
To study whether recombinant human erythropoietin can pass through mice blood-retina barrier and the protective role in light-induced damage in retina.


METHODS
After the injection of rHEPO, the content of rHEPO in 24 BALB/c mice retina was examined by enzyme linked immunosorbent assay (ELISA). 24 BALB/c mice were used to establish a light-induced damaged model, the difference of retina in rHEPO group and control group was compared using light microscope and TdT-mediated dUTP nick end labeling (TUNEL).


RESULTS
The amount of retinal rHEPO in four deferent time points was (0.68 +/- 0.24) mU, (1.87 +/- 0.37) mU, (0.96 +/- 0.24) mU, (0.47 +/- 0.13) mU in 100 microg retinal total protein respectively by ELISA assay, there were statistical significances among groups. The density of rHEPO in the retina reached its peak at 4th hour after injection. Histology analysis: rHEPO group, at the 12th hour after light exposure the inner segment became condensed and disorganized. At the 36th hour the retina disorganized and vesiculated were seen in outer segments. At the 72nd hour the inner and outer segments were damaged more seriously and the outer nuclear layer became thinner and denser. On the 7th day, the retinal outer nuclear layer became thinner and condenses. rHEPO group showed a minimal damage in every time points but outer nuclear layer disorganized and vesiculated in inner and outer segments. No obvious changes in retinal thickness. The apoptotic cells were detected by TUNEL. At the 12th hour after light exposure, there were the apoptotic cells in outer nuclear layer near outer plexiform layer. At 36th hour the numbers of apoptotic cells were increased, however at the 72nd it was decreased obviously, only a few scattering apoptotic cells were revealed in the outer nuclear layer. Numbers of apoptotic cells between the rHEPO group and control group in outer nuclear layer were statistical significance (P < 0.01).


CONCLUSIONS
rHEPO can pass through the mice blood-retina barrier and rHEPO has neuroprotective effect on mice retina. rHEPO may be used to treat degenerative retinal diseases.
Wang
Hong-yun
HY
Department of Ophthalmology, the Affiliated Hospital, the Medical School of Qingdao University, Qingdao 266003, China.
Niu
Ying-jun
YJ
Wang
Pei-song
PS
Zhou
Zhan-yu
ZY
Liu
Fu-ling
FL
Yang
Wen-yi
WY
Zhang
Yue-hong
YH
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001813:Blood-Retinal Barrier; D004921:Erythropoietin / Q000494:pharmacology*; D005260:Female; D008027:Light / Q000009:adverse effects; D008297:Male; D051379:Mice; D020419:Photoreceptor Cells, Vertebrate / Q000187:drug effects; D011994:Recombinant Proteins; D012160:Retina / Q000473:pathology*; D012162:Retinal Degeneration / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*
D011994:Recombinant Proteins; D004921:Erythropoietin