title: Prolongation of life span in the accelerated aging klotho mouse model, by low-dose-rate continuous γ irradiation.
abstract: While lifespan studies provide basic information for estimating the risk of ionizing radiation, findings on the effect of low-dose/low-dose-rate irradiation on the lifespan of mammals are controversial. Here we evaluate the effect of continuous exposure to low-dose-rate γ radiation on the lifespan of mice with accelerated aging caused by mutation of the klotho gene. While control mice died within 80 days after birth, more than 10% of mice exposed continuously to 0.35 or 0.7 or mGy/h γ radiation from 40 days after birth survived for more than 80 days. Two of 50 mice survived for more than 100 days. Low-dose-rate irradiation significantly increased plasma calcium concentration in mutant mice, and concomitantly increased hepatic catalase activity. Although hepatic activity of superoxide dismutase in mutant mice decreased significantly compared to wild-type mice, continuous γ irradiation decreased the activity in mutant mice significantly. These results suggest that low-dose-rate ionizing radiation can prolong the lifespan of mice in certain settings.
authors.affiliation: Radiation Safety Research Center, Nuclear Technology Research Laboratory, Central Research Institute of Electric Power Industry, 2-11-1 Iwado Kita, Komae, Tokyo 201-8511, Japan.
authors.forename: Takaharu
authors.initials: T
authors.lastname: Nomura
authors.forename: Kazuo
authors.initials: K
authors.lastname: Sakai
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Ogata
authors.forename: Junji
authors.initials: J
authors.lastname: Magae
mesh_terms: D000054:Acceleration; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001835:Body Weight / Q000528:radiation effects; D015519:Bone Density / Q000528:radiation effects; D002118:Calcium / Q000097:blood; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005720:Gamma Rays / Q000009:adverse effects*; D008099:Liver / Q000254:growth & development / Q000378:metabolism / Q000528:radiation effects; D008136:Longevity / Q000502:physiology / Q000528:radiation effects*; D051379:Mice; D009929:Organ Size / Q000528:radiation effects
chemical_list: D000975:Antioxidants; D002118:Calcium