title: Heat-treated mineral-yeast as a potent post-irradiation radioprotector.
abstract: In vivo radioprotection of C3H mice by i.p. administration of Zn-, Mn-, Cu-, or Se-containing heat-treated Saccharomyces serevisiae yeast sample was examined. The 30-day survival of the group treated 30 min before 7.5 Gy whole-body X-irradiation with mineral-containing yeast powders suspended in 0.5% methylcellulose was significantly higher than that of control group. When mineral-yeast was administered immediately after irradiation, the survival rate was even higher and Zn- or Cu-yeast showed the highest rate (more than 90%). Although treatment with simple yeast showed a high survival rate (73%), it was significantly lower than that obtained by the Zn-yeast treatment. The effects of Zn-yeast were studied further. When the interval between irradiation and administration was varied, the protective activity of Zn-yeast decreased gradually by increasing the interval but was still significantly high for the administration at 10 h post-irradiation. The dose reduction factor of Zn-yeast (100 mg/kg, i.p. administration immediately after irradiation) was about 1.2. When the suspension of Zn-yeast was fractionated by centrifugation, the insoluble fraction showed a potent effect, while the soluble fraction had only a moderate effect. In conclusion, mineral-yeast, especially Zn-yeast, provides remarkable post-irradiation protection against lethal whole body X-irradiation. The activity is mainly attributable to the insoluble fraction, whereas some soluble components might contribute to the additional protective activity.
authors.affiliation: Research Center for Charged Particle Therapy, National Institute of Radiological Sciences. anzai@nirs.go.jp
authors.forename: Kazunori
authors.initials: K
authors.lastname: Anzai
authors.forename: Nobuo
authors.initials: N
authors.lastname: Ikota
authors.forename: Megumi
authors.initials: M
authors.lastname: Ueno
authors.forename: Minako
authors.initials: M
authors.lastname: Nyui
authors.forename: Tsutomu V
authors.initials: TV
authors.lastname: Kagiya
mesh_terms: D000818:Animals; D004307:Dose-Response Relationship, Radiation; D006358:Hot Temperature; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D008903:Minerals / Q000008:administration & dosage* / Q000737:chemistry; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000517:prevention & control*; D011837:Radiation-Protective Agents / Q000008:administration & dosage*; D012441:Saccharomyces cerevisiae / Q000737:chemistry*; D016019:Survival Analysis; D015996:Survival Rate
chemical_list: D008903:Minerals; D011837:Radiation-Protective Agents