title: Erythropoietin attenuates hyperoxia-induced oxidative stress in the developing rat brain.
abstract: Oxygen toxicity contributes to the pathogenesis of adverse neurological outcome in survivors of preterm birth in clinical studies. In infant rodent brains, hyperoxia triggers widespread apoptotic neurodegeneration, induces pro-inflammatory cytokines and inhibits growth factor signaling cascades. Since a tissue-protective effect has been observed for recombinant erythropoietin (rEpo), we hypothesized that rEpo would influence hyperoxia-induced oxidative stress in the developing rat brain. The aim of this study was to investigate the level of glutathione (reduced and oxidized), lipid peroxidation and the expression of heme oxygenase-1 (HO-1) and acetylcholinesterase (AChE) after hyperoxia and rEpo treatment. Six-day-old Wistar rats were exposed to 80% oxygen for 2-48 h and received 20,000 IU/kg rEpo intraperitoneally (i.p.). Sex-matched littermates kept under room air and injected with normal saline or rEpo served as controls. Treatment with rEpo significantly reduced hyperoxia-induced upregulation of oxidized glutathione (GSSG) and malondialdehyde, a product of lipid breakdown, whereas reduced glutathione (GSH) was upregulated by rEpo. In parallel, hyperoxia-treated immature rat brains revealed rEpo-suppressible upregulation of synaptic AChE-S as well as of the stress-inducible AChE-R variant, together predicting rEpo-protected cholinergic signaling and restrained inflammatory reactions. Furthermore, treatment with rEpo induced upregulation of HO-1 on mRNA, protein and activity level in the developing rat brain. Our results suggest that rEpo generates its protective effect against oxygen toxicity by a reduction of diverse oxidative stress parameters and by limiting the stressor-inducible changes in both HO-1 and cholinergic functions.
authors.affiliation: Department of Neonatology, Charité-Universitätsmedizin Berlin, Berlin, Germany. marco.sifringer@charite.de
authors.forename: Marco
authors.initials: M
authors.lastname: Sifringer
authors.forename: Daniela
authors.initials: D
authors.lastname: Brait
authors.forename: Ulrike
authors.initials: U
authors.lastname: Weichelt
authors.forename: Gabriel
authors.initials: G
authors.lastname: Zimmerman
authors.forename: Stefanie
authors.initials: S
authors.lastname: Endesfelder
authors.forename: Felix
authors.initials: F
authors.lastname: Brehmer
authors.forename: Clarissa
authors.initials: C
authors.lastname: von Haefen
authors.forename: Alon
authors.initials: A
authors.lastname: Friedman
authors.forename: Hermona
authors.initials: H
authors.lastname: Soreq
authors.forename: Ivo
authors.initials: I
authors.lastname: Bendix
authors.forename: Bettina
authors.initials: B
authors.lastname: Gerstner
authors.forename: Ursula
authors.initials: U
authors.lastname: Felderhoff-Mueser
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D001921:Brain / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D004921:Erythropoietin / Q000494:pharmacology* / Q000627:therapeutic use; D005260:Female; D005978:Glutathione / Q000378:metabolism; D051547:Heme Oxygenase-1 / Q000378:metabolism; D018496:Hyperoxia / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
chemical_list: D011994:Recombinant Proteins; D004921:Erythropoietin; D051547:Heme Oxygenase-1; D005978:Glutathione