Artikel
Trophic Effects of Erythropoietin on the Retinal Pigmentepithelium
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Veröffentlicht: | 18. Juni 2008 |
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Gliederung
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Background: Oxidative damage of the retinal pigmentepithelium (RPE) plays an important role in the etiology of age related macula degeneration. In the following study trophic effects of erythropoietin (EPO) at oxidative stressed RPE cells are investigated and compared with the protective properties of scavenger molecules.
Methods: Hydroxylradicals are generated from the Fenton reaction. The radical concentration will be given as multiples of a reference concentration which was examined by NMR spectroscopy previously. Survival rate (life dead assay) and apoptosis rate (TUNEL assay and Annexin V labelling) was measured in cultured ARPE-19 cells. The experiments were done in absence and presence of pharmacological test compounds. The EPO-Receptor was detected by Western blotting.
Results: Several hours after radical exposure apoptosis can be observed. Apoptosis rate reaches its maximum after 6 hours (11.8±1.7% at 3x radical concentration; P<0.05). Scavengers like vitamin C do not have protective properties. Particularly in low concentrations below 1mM they may increase the oxidative damage (cell survival rate without vitamin C 87±1% to 89±2% vs. 79±2% to 82±3% in presence of 0.1 to 1mM vitamin C; n=6 each; P<0.05). EPO reduces apoptosis rate after 6 hours significantly (12.5±0.9% w/o EPO vs. 4.0±0.8% with 5U/ml EPO; P=0.02; n=3 each). EPO is still effective if i given after radical exposure. Western blot confirmed the presence of the EPO-receptor.
Conclusions: EPO prevents RPE cells from oxidative induced apoptosis, while prevention of radical induced cell death by administration of scavengers failed.