title: Promotion of neurite outgrowth and protective effect of erythropoietin on the retinal neurons of rats.
abstract: OBJECTIVE
  To clarify the effect of erythropoietin (EPO) on neurite outgrowth of the cultured retinal neurocytes, and investigate whether EPO might potentially be beneficial in protecting cultured retinal neurocytes suffering from glutamate-induced cytotoxity.
  
  
  METHODS
  After the retinal neurocytes were cultured for 48 hours, the culture media was replaced with serum-free media, and the cultured retinal cells were exposed to 1.0 U/ml, 3.0 U/ml and 6.0 U/ml EPO for another 48 hours; then the cells were stained with Sudan Black B, and the neurite outgrowth of those cells were evaluated by an image-analysis system. After the retinal neurocytes were cultured for 48 hours, the cells were cultured in serum-free media containing 5 mM or 10 mM glutamate, and the cells were incubated in the presence or absence of Epo (1.0 U/ml, 3.0 U/ml, 6.0 U/ml respectively) for another 48 hours. The survival and apoptosis rates of those cells were estimated by MTT assay and fluorescein isothiocyanate (FITC)-annexin V/propidium Iodide (PI) flow cytometry respectively.
  
  
  RESULTS
  EPO induced a stable improvement of neurite outgrowth of retinal neurocytes in a dose-dependent manner. Compared with the control group, the neurite outgrowth length increased to 162.8% at 6.0 U/ml EPO exposure. EPO had no any significant effect on the survival and apoptosis rates of the retinal neurocytes cultured in serum-free media, but it was beneficial in promoting the survival and decreasing the early and total apoptosis rates of the cultured retinal neurocytes suffering from glutamate-induced cytotoxicity.
  
  
  CONCLUSIONS
  EPO had a significant biological effect on neurite outgrowth of the dissociated retinal neurocytes in vitro. EPO was beneficial in promoting the survival and decreasing the apoptosis rates of the cultured retinal neurocytes suffering from glutamate-induced cytotoxicity.
authors.affiliation: Department of Ophthalmology, Ruijin Hospital Affiliated Shanghai Jiaotong University, 197 Ruijin No.2 Road, 200025, Shanghai, People's Republic of China. yszhong68@yahoo.com.cn
authors.forename: Yisheng
authors.initials: Y
authors.lastname: Zhong
authors.forename: Huiping
authors.initials: H
authors.lastname: Yao
authors.forename: Lianfu
authors.initials: L
authors.lastname: Deng
authors.forename: Yu
authors.initials: Y
authors.lastname: Cheng
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Zhou
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects; D018929:Cell Culture Techniques; D002470:Cell Survival / Q000187:drug effects; D016895:Culture Media, Serum-Free; D004305:Dose-Response Relationship, Drug; D004921:Erythropoietin / Q000494:pharmacology*; D005434:Flow Cytometry; D018698:Glutamic Acid / Q000633:toxicity; D009416:Nerve Regeneration / Q000502:physiology; D016501:Neurites / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012165:Retinal Ganglion Cells / Q000187:drug effects*