Recovery of motor spontaneous activity after intranasal delivery of human recombinant erythropoietin in a focal brain hypoxia model induced by CoCl2 in rats.
Stroke is a major human health problem inducing long-term disability without any efficient therapeutic option being currently available. Under hypoxia, hypoxia-inducible factor-1α (HIF-1α) activates several genes as erythropoietin receptor (Epo-R) related with O(2) supply, and the multidrug-resistance gene (MDR-1) related with drug-refractory phenotype. Brain cortical injection of CoCl(2) produces focal hypoxia-like lesion with neuronal and glial alterations, as well as HIF-1α stabilization and MDR-1 overexpression. Intranasal (IN) drug delivery can by-pass blood-brain barrier (BBB) where MDR-1 is normally expressed. We evaluated the effects of IN-rHu-Epo administration on spontaneous motor activity (SMA) and the brain pattern expression of HIF-1α, MDR-1, and Epo-R in our cobalt-induced hypoxia model. Adult male Wistar rats were injected by stereotaxic surgery in frontoparietal cortex, with CoCl(2) (2 μl-50 mM; n = 20) or saline (controls; n = 20). Ten rats of each group were treated with IN-rHu-Epo 24 U or IN-saline. In addition, erythropoietic stimulation was evaluated by reticulocytes (Ret) account during three consecutive days, after intraperitoneal (i.p.)-recombinant-human Epo (rHu-Epo) (950 U; n = 6) or IN-rHu-Epo (24 U; n = 6) administration. SMA was evaluated by open field and rotarod tests, before and after surgical procedures during five consecutive days. Histological and immunostaining studies of HIF-1α, MDR-1, and Epo-R were performed on brain slides. A significant difference in SMA was observed in the hypoxic rats of IN-rHu-Epo-administered group as compared with Co-Saline-treated subjects and controls (p < 0.001). HIF-1α, EPO-R, and MDR-1 were overexpressed in the hypoxic cortex areas, while in contralateral hemisphere or controls, they were negatives. Reticulocytes were only increased in intraperitoneal (i.p.)-rHu-Epo-administered group. In spite of MDR-1 overexpression being detected in neurons, the coexpression of Epo-R could explain the positive effects observed on SMA of IN-rHu-Epo-administered group.
Instituto de Biología Celular y Neurociencias Prof. E. De Robertis, Facultad de Medicina, UBA-CONICET, Calle Paraguay 2155, 3er piso, C1121ABG, Buenos Aires, Argentina.
Amalia
A
Merelli
Laura
L
Caltana
Patricia
P
Girimonti
Alberto Javier
AJ
Ramos
Alberto
A
Lazarowski
Alicia
A
Brusco
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D000281:Administration, Intranasal; D000704:Analysis of Variance; D000818:Animals; D003035:Cobalt / Q000633:toxicity*; D004195:Disease Models, Animal; D004921:Erythropoietin / Q000008:administration & dosage*; D005106:Exploratory Behavior / Q000187:drug effects*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D002534:Hypoxia, Brain / Q000139:chemically induced* / Q000188:drug therapy*; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D017467:Receptors, Erythropoietin / Q000378:metabolism; D011994:Recombinant Proteins; D020127:Recovery of Function / Q000187:drug effects*; D012156:Reticulocytes / Q000187:drug effects; D045442:Rotarod Performance Test
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D017467:Receptors, Erythropoietin; D011994:Recombinant Proteins; D004921:Erythropoietin; D003035:Cobalt; C018021:cobaltous chloride