Radioprotection mediated by the haemopoietic stimulation conferred by AM5: a protein-associated polysaccharide.
The haemopoietic and radioprotective effects of a protein-associated polysaccharide named AM5, have been studied following i.v. injection in mice. A dose-related accumulation of the splenic granulocyte-macrophage colony-forming units (CFU-GM) and colony-forming units in the spleen (CFU-S) was observed in mice treated with doses ranging from 0.1 to 0.4 mg/kg of AM5. The accumulation of splenic CFU-S, CFU-GM and BFU-e (erythroid burst-forming units) was always maximal 5 days after treatment with 0.4 mg/kg of AM5, with increases over control values between 300% and 500%. When the number of haemopoietic progenitors was quantified in the bone marrow, only slight increases of CFU-S were obtained, corresponding to the administration of low doses of AM5 (0.1 mg/kg). However, significant increases of circulating CFU-S were observed following administration of higher doses of AM5, suggesting a mobilization of haemopoietic progenitors from this organ. A faster recovery of spleen CFU-GM was observed in mice treated with 0.4 mg/kg of AM5 3 days or 1 day prior to a sublethal irradiation, and at this later time AM5 produced a significant survival enhancement from 10% to 90% in mice irradiated with 7.6 Gy X-rays. This effect was correlated with an increase in the nadir of leucocytes, characteristic of the radiation syndrome.
Real
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A
CIEMAT, Instituto de Medio Ambiente, Madrid, Spain.
Güenechea
G
G
Bueren
J A
JA
Maganto
G
G
D000818:Animals; D006410:Hematopoiesis / Q000187:drug effects*; D007275:Injections, Intravenous; D008297:Male; D008351:Mannans / Q000627:therapeutic use*; D051379:Mice; D011837:Radiation-Protective Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D013268:Stimulation, Chemical; D015996:Survival Rate
C075974:AM5; D008351:Mannans; D011837:Radiation-Protective Agents