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Published on: February 8, 2016
Heat-treated mineral-yeast as a potent post-irradiation radioprotector
Kazunori Anzai1, Nobuo Ikota, Megumi Ueno
1Research Center for Charged Particle Therapy, National Institute of Radiological Sciences. anzai@nirs.go.jp
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.
Insights
Heat-treated Saccharomyces cerevisiae yeast containing minerals, particularly zinc, significantly enhances survival after lethal X-irradiation in mice. This radioprotective effect is most potent when administered shortly after exposure.
Area of Science:
- Radiobiology
- Biochemistry
- Microbiology
Background:
- Whole-body X-irradiation poses significant health risks.
- Developing effective radioprotective agents is crucial for radiation protection.
- Saccharomyces cerevisiae yeast and its mineral components are explored for biological activities.
Purpose of the Study:
- To investigate the in vivo radioprotective effects of heat-treated Saccharomyces cerevisiae yeast containing various minerals (Zn, Mn, Cu, Se).
- To evaluate the efficacy of mineral-yeast administration before and after X-irradiation.
- To determine the optimal conditions and active components for radioprotection.
Main Methods:
- C3H mice were administered mineral-containing or simple yeast suspensions via intraperitoneal injection.
- Mice were subjected to whole-body X-irradiation at a lethal dose (7.5 Gy).
- Survival rates were assessed over 30 days; dose reduction factor and fractionated Zn-yeast effects were also analyzed.
Main Results:
- Mineral-containing yeast significantly increased 30-day survival compared to controls.
- Administration immediately after irradiation yielded higher survival rates, with Zn- and Cu-yeast showing over 90% survival.
- Zn-yeast demonstrated significant protective activity up to 10 hours post-irradiation, with a dose reduction factor of approximately 1.2.
Conclusions:
- Heat-treated mineral-yeast, especially zinc-enriched yeast, offers remarkable radioprotection against lethal X-irradiation.
- The insoluble fraction of Zn-yeast exhibited potent radioprotective activity, suggesting its primary role.
- Soluble components may contribute additional protective benefits, warranting further investigation.
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