title: Progenitors mobilized by gamma-tocotrienol as an effective radiation countermeasure.
abstract: The purpose of this study was to elucidate the role of gamma-tocotrienol (GT3)-mobilized progenitors in mitigating damage to mice exposed to a supralethal dose of cobalt-60 gamma-radiation. CD2F1 mice were transfused 24 h post-irradiation with whole blood or isolated peripheral blood mononuclear cells (PBMC) from donors that had received GT3 72 h prior to blood collection and recipient mice were monitored for 30 days. To understand the role of GT3-induced granulocyte colony-stimulating factor (G-CSF) in mobilizing progenitors, donor mice were administered a neutralizing antibody specific to G-CSF or its isotype before blood collection. Bacterial translocation from gut to heart, spleen and liver of irradiated recipient mice was evaluated by bacterial culture on enriched and selective agar media. Endotoxin in serum samples also was measured. We also analyzed the colony-forming units in the spleens of irradiated mice. Our results demonstrate that whole blood or PBMC from GT3-administered mice mitigated radiation injury when administered 24 h post-irradiation. Furthermore, administration of a G-CSF antibody to GT3-injected mice abrogated the efficacy of blood or PBMC obtained from such donors. Additionally, GT3-mobilized PBMC inhibited the translocation of intestinal bacteria to the heart, spleen, and liver, and increased colony forming unit-spleen (CFU-S) numbers in irradiated mice. Our data suggests that GT3 induces G-CSF, which mobilizes progenitors and these progenitors mitigate radiation injury in recipient mice. This approach using mobilized progenitor cells from GT3-injected donors could be a potential treatment for humans exposed to high doses of radiation.
authors.affiliation: Armed Forces Radiobiology Research Institute, Bethesda, Maryland, United States of America; Department of Radiation Biology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America.
authors.forename: Vijay K
authors.initials: VK
authors.lastname: Singh
authors.affiliation: Armed Forces Radiobiology Research Institute, Bethesda, Maryland, United States of America.
authors.forename: Stephen Y
authors.initials: SY
authors.lastname: Wise
authors.affiliation: Armed Forces Radiobiology Research Institute, Bethesda, Maryland, United States of America.
authors.forename: Oluseyi O
authors.initials: OO
authors.lastname: Fatanmi
authors.affiliation: Armed Forces Radiobiology Research Institute, Bethesda, Maryland, United States of America.
authors.forename: Jessica
authors.initials: J
authors.lastname: Scott
authors.affiliation: Armed Forces Radiobiology Research Institute, Bethesda, Maryland, United States of America.
authors.forename: Patricia L P
authors.initials: PL
authors.lastname: Romaine
authors.affiliation: Armed Forces Radiobiology Research Institute, Bethesda, Maryland, United States of America.
authors.forename: Victoria L
authors.initials: VL
authors.lastname: Newman
authors.affiliation: Armed Forces Radiobiology Research Institute, Bethesda, Maryland, United States of America.
authors.forename: Amit
authors.initials: A
authors.lastname: Verma
authors.affiliation: Armed Forces Radiobiology Research Institute, Bethesda, Maryland, United States of America.
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Elliott
authors.affiliation: Tech Micro Services, Bethesda, Maryland, United States of America.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Seed
mesh_terms: D000818:Animals; D002839:Chromans / Q000494:pharmacology*; D003037:Cobalt Radioisotopes / Q000633:toxicity; D008297:Male; D051379:Mice; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D013234:Stem Cells / Q000187:drug effects / Q000528:radiation effects*; D014810:Vitamin E / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D002839:Chromans; D003037:Cobalt Radioisotopes; D011837:Radiation-Protective Agents; D014810:Vitamin E; C013649:plastochromanol 8