title: Hypoxia-ischemia affects erythropoietin and erythropoietin receptor expression pattern in the neonatal rat brain.
abstract: Erythropoietin (EPO), known for its role in erythroid differentiation, has been suggested to have non-hematopoietic functions in the brain, especially during development. In the present study, we investigated the expression of erythropoietin and erythropoietin receptor (EPOR) in the developing rat brain following hypoxia-ischemia. Seven-day-old rats underwent unilateral, permanent carotid artery ligation followed by 1 h of hypoxia, and their brains were examined immediately, 24 h or 4 days after hypoxia-ischemia. RT-PCR and Western blot analysis revealed that hypoxia-ischemia only marginally affected EPO expression. Immunohistochemical study of brains 4 days after hypoxia showed that 60 min of hypoxia (resulting in cortical infarction and severe neuronal loss in other regions) led to the increased EPO immunoreactivity, especially in the boundaries of the damaged cerebral cortex, associated with astrocytosis. In contrast, EPOR was dramatically upregulated within 24 h after hypoxia-ischemia. These results suggest that there is a rapid response of EPOR to the hypoxic-ischemic stimulus, which seems to precede that of EPO, leading to the hypothesis that the EPO/EPOR system is implicated in the processes of neuroprotection from hypoxia-ischemia.
authors.affiliation: Department of Physiology and Pharmacology, Faculty of Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece. spandou@med.auth.gr
authors.forename: Evangelia
authors.initials: E
authors.lastname: Spandou
authors.forename: Stamatia
authors.initials: S
authors.lastname: Papoutsopoulou
authors.forename: Vassiliki
authors.initials: V
authors.lastname: Soubasi
authors.forename: George
authors.initials: G
authors.lastname: Karkavelas
authors.forename: Constantina
authors.initials: C
authors.lastname: Simeonidou
authors.forename: George
authors.initials: G
authors.lastname: Kremenopoulos
authors.forename: Olympia
authors.initials: O
authors.lastname: Guiba-Tziampiri
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D002339:Carotid Arteries / Q000601:surgery; D004921:Erythropoietin / Q000096:biosynthesis*; D005786:Gene Expression Regulation; D005911:Gliosis / Q000209:etiology; D020925:Hypoxia-Ischemia, Brain / Q000150:complications / Q000378:metabolism* / Q000473:pathology*; D007150:Immunohistochemistry; D008026:Ligation; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017467:Receptors, Erythropoietin / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
chemical_list: D012333:RNA, Messenger; D017467:Receptors, Erythropoietin; D004921:Erythropoietin