title: Time-dependent effect of combination therapy with erythropoietin and granulocyte colony-stimulating factor in a mouse model of hypoxic-ischemic brain injury.
abstract: Erythropoietin (EPO) and granulocyte colony-stimulating factor (G-CSF) are likely to play broad roles in the brain. We investigated the effects of combination therapy with EPO and G-CSF in hypoxic-ischemic brain injury during the acute, subacute, and chronic phases. A total of 79 C57BL/6 mice with hypoxic-ischemic brain injury were randomly assigned acute (days 1-5), subacute (days 11-15) and chronic (days 28-32) groups. All of them were treated with G-CSF (250 μg/kg) and EPO (5000 U/kg) or saline daily for 5 consecutive days. Behavioral assessments and immunohistochemistry for angiogenesis, neurogenesis, and astrogliosis were performed with an 8-week follow-up. Hypoxia-inducible factor-1 (HIF-1) was also measured by Western blot analysis. The results showed that the combination therapy with EPO and G-CSF in the acute phase significantly improved rotarod performance and forelimb-use symmetry compared to the other groups, while subacute EPO and G-CSF therapy exhibited a modest improvement compared with the chronic saline controls. The acute treatment significantly increased the density of CD31(+) (PECAM-1) and α-smooth muscle actin(+) vessels in the frontal cortex and striatum, increased BrdU(+)/PSA-NCAM(+) neurogenesis in the subventricular zone, and decreased astroglial density in the striatum. Furthermore, acute treatment significantly increased the HIF-1 expression in the cytosol and nucleus, whereas chronic treatment did not change the HIF-1 expression, consistent with the behavioral outcomes. These results indicate that the induction of HIF-1 expression by combination therapy with EPO and G-CSF synergistically enhances not only behavioral function but also neurogenesis and angiogenesis while decreasing the astroglial response in a time-dependent manner.
authors.affiliation: Department and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Ji Hea
authors.initials: JH
authors.lastname: Yu
authors.forename: Jung Hwa
authors.initials: JH
authors.lastname: Seo
authors.forename: Jong Eun
authors.initials: JE
authors.lastname: Lee
authors.forename: Ji Hoe
authors.initials: JH
authors.lastname: Heo
authors.forename: Sung-Rae
authors.initials: SR
authors.lastname: Cho
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects*; D004195:Disease Models, Animal; D004359:Drug Therapy, Combination; D004921:Erythropoietin / Q000627:therapeutic use*; D016179:Granulocyte Colony-Stimulating Factor / Q000627:therapeutic use*; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D020925:Hypoxia-Ischemia, Brain / Q000188:drug therapy*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009043:Motor Activity / Q000187:drug effects; D055495:Neurogenesis / Q000187:drug effects; D018696:Neuroprotective Agents / Q000627:therapeutic use*
chemical_list: C497443:Hif1a protein, mouse; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D018696:Neuroprotective Agents; D004921:Erythropoietin; D016179:Granulocyte Colony-Stimulating Factor