Böcker-Meffert Simone, Rosenstiel Philip, Röhl Claudia, Warneke Nils, Held-Feindt Janka, Sievers Jobst, Lucius Ralph
Institute of Anatomy, Christian-Albrechts-University of Kiel, Kiel, Germany.
Invest Ophthalmol Vis Sci. 2002 Jun;43(6):2021-6.
Recent studies have reported neuroprotective effects of erythropoietin (EPO) and vascular endothelial growth factor (VEGF). The purpose of the present study was to clarify their influence on neurite outgrowth and regeneration of rat retinal ganglion cells (RGCs) in vitro and to elucidate the expression of corresponding receptors in the rat retina in vivo.
Retinal explants from postnatal rats were stimulated with VEGF alone; VEGF in combination with anti-VEGF-receptor (VEGF-R)-2 antibody or T-type Ca2+ channel blocker ethosuximide (ESX); EPO alone; or EPO in combination with anti-EPO-receptor antibody or ESX. The presence of the corresponding receptors in the rat retina was assessed by reverse transcription-polymerase chain reaction (RT-PCR) and by immunohistochemistry.
EPO induced a stable improvement of neurite outgrowth of RGCs in a dose-dependent manner (5 x 10(-15) M to 5 x 10(-13) M) up to 169% (P < 0.05). Treatment of the explants with anti-EPO-R antibody (1:80 dilution) and with ESX (5 microM) totally inhibited EPO-mediated effects on RGCs. In comparison, VEGF (50 ng/mL), induced neurite outgrowth of retina explants up to 167% (P < 0.05), which again was inhibited in the presence of anti-VEGF-R2 antibody or ESX. Transcripts of EPO-R, VEGF-R1, and VEGF-R2 were detected by RT-PCR. Intense immunoreactivity for VEGF-R1, VEGF-R2, and EPO-R were found in the RGC layer of the retina.
The data demonstrate for the first time that EPO and VEGF have a significant and specific biological effect on neurite regrowth of axotomized RGCs. Therefore, these results imply that EPO and VEGF have not only a neuroprotective but also a neuroregenerative role in ischemic retinal conditions.
近期研究报道了促红细胞生成素（EPO）和血管内皮生长因子（VEGF）的神经保护作用。本研究的目的是阐明它们对大鼠视网膜神经节细胞（RGCs）体外神经突生长和再生的影响，并阐明相应受体在大鼠视网膜体内的表达情况。
用单独的VEGF；VEGF与抗VEGF受体（VEGF-R）-2抗体或T型Ca2+通道阻滞剂乙琥胺（ESX）联合使用；单独的EPO；或EPO与抗EPO受体抗体或ESX联合使用刺激新生大鼠的视网膜外植体。通过逆转录聚合酶链反应（RT-PCR）和免疫组织化学评估大鼠视网膜中相应受体的存在情况。
EPO以剂量依赖性方式（5×10-15 M至5×10-13 M）诱导RGCs神经突生长稳定改善，最高可达169%（P<0.05）。用抗EPO-R抗体（1:80稀释）和ESX（5μM）处理外植体完全抑制了EPO对RGCs的介导作用。相比之下，VEGF（50 ng/mL）诱导视网膜外植体神经突生长最高可达167%（P<0.05），在抗VEGF-R2抗体或ESX存在时再次受到抑制。通过RT-PCR检测到EPO-R、VEGF-R1和VEGF-R2的转录本。在视网膜的RGC层中发现了VEGF-R1、VEGF-R2和EPO-R的强烈免疫反应性。
数据首次证明EPO和VEGF对轴突切断的RGCs的神经突再生具有显著且特异性的生物学效应。因此，这些结果表明EPO和VEGF在缺血性视网膜疾病中不仅具有神经保护作用，还具有神经再生作用。
