title: Effects of supplemental erythropoietin on its receptor expression and signal transduction pathways in rat model of retinal detachment.
abstract: OBJECTIVE
  The aim of this study was to investigate the effects of supplemental erythropoietin (EPO) on its receptor (EPOR) and signal transduction pathways in rat model of retinal detachment (RD).
  
  
  METHODS
  To investigate the effect of EPO on EPOR expression in RD rats 100, 200 or 400 ng EPO was injected into the vitreous cavity immediately after RD model was induced. Western blot and immunohistochemistry analyses were performed to measure EPOR expression. To investigate the effect of EPO on signal transduction pathways in RD rats single dose of 400 ng EPO was injected into the vitreous cavity immediately after RD model was induced. The total and phosphorylated levels of JAK2, Akt, ERK-1/2, STAT5 and NF-κB were assessed by western blot.
  
  
  RESULTS
  Western blot analysis showed that, compared with the normal control group, EPOR expression in the neurosensory retina was significantly increased in experimental RD groups (P < 0.05), but the differences were not significant between experimental RD groups (P > 0.05). Immunohistochemical examination indicated that EPOR staining on retinas became strongly positive 3 days after RD, with no significant difference in staining intensities between the treatment groups. Phosphorylated levels of JAK2, Akt, ERK-1/2, STAT5, and NF-κB were enhanced 3 days after RD, but only JAK2, Akt, and ERK-1/2 phosphorylation was further enhanced by 400 ng EPO treatment (P < 0.05).
  
  
  CONCLUSIONS
  Supplementary EPO cannot affect EPOR expression in detached retina, but EPO may activate both PI-3K/Akt and MAPK/ERK-1/2 signal transduction pathways in RD model.
authors.affiliation: Department of Ophthalmology, Clinical Medicine School, Yangzhou University, Subei People's Hospital of Jiangsu Province, Yangzhou, China. zgxie87@163.com
authors.forename: Zhenggao
authors.initials: Z
authors.lastname: Xie
authors.forename: Fang
authors.initials: F
authors.lastname: Chen
authors.forename: Xingwei
authors.initials: X
authors.lastname: Wu
authors.forename: Chaorong
authors.initials: C
authors.lastname: Zhuang
authors.forename: Jun
authors.initials: J
authors.lastname: Zhu
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Heqing
authors.initials: H
authors.lastname: Ji
authors.forename: Yakun
authors.initials: Y
authors.lastname: Wang
authors.forename: Xin
authors.initials: X
authors.lastname: Hua
mesh_terms: D000818:Animals; D015153:Blotting, Western; D004195:Disease Models, Animal; D004921:Erythropoietin / Q000494:pharmacology*; D007150:Immunohistochemistry; D058449:Intravitreal Injections; D053614:Janus Kinase 2 / Q000378:metabolism; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017467:Receptors, Erythropoietin / Q000378:metabolism*; D012163:Retinal Detachment / Q000378:metabolism*; D050799:STAT5 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D015854:Up-Regulation
chemical_list: D016328:NF-kappa B; D017467:Receptors, Erythropoietin; D050799:STAT5 Transcription Factor; D004921:Erythropoietin; C507927:Jak2 protein, rat; D053614:Janus Kinase 2; D051057:Proto-Oncogene Proteins c-akt; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3