報告書番号

G02002

タイトル（和文）

II型糖尿病モデルマウスに対する低線量率放射線の照射効果の検証

タイトル（英文）

Effect of Low-Dose Rate Irradiation on Type II Diabetes Model Mice

概要 （図表や脚注は「報告書全文」に掲載しております）

過食などにより引き起こされるII型糖尿病に対し、低線量放射線の照射で糖尿病の改善などの効果が得られるか検討した。II型糖尿病のモデルマウス(C56BL/KsJ-db/db)に対し、低線量率放射線長期照射設備のセシウム-137を線源とするγ線を線量率0.65 mGy/hrで1群12匹、10週齢から照射し続けた。その結果12例中3例で改善効果が見られ、早いマウスでは35週齢で、遅いマウスでも80週齢で尿糖値の改善が認められた。一方非照射野で飼育した12匹の同じモデルマウスでは、尿糖値の改善効果はなかった。尿糖値の改善したマウスの体重の変化、摂食量や飲水量は非照射群の場合と異なる変化は認められなかった。マウスの生存率は照射群の方に寿命の延長が認められ、また低脱毛率などの老化の抑制効果が見られた。これらの結果は尿糖値改善とは関係なく、低線量率照射が加齢に及ぼす新たな現象の可能性と考えられる。

概要 （英文）

The effects of low dose rate gamma-irradiation were investigated on model mice for type II diabetes mellitus, C57BL/KsJ-db+/db+. The mice develop the type II diabetes by 10 weeks of age due to obesity and are characterized by hyperinsulinemia.Female 10-week old mice, a group of 12, were irradiated at 0.65 mGy/hr in the low dose rate irradiation facility in Low Dose Radiation Research Center. The level of urine glucose was measured with test slips. The urine glucose levels of all of the mice were strongly positive at the beginning of the irradiation. In the irradiated group, the decrease in the glucose level was observed in 3 mice, one in 35th week, another in 52nd week, the other in 80th week. Such recovery from the diabetes was never observed in 12 mice of non-irradiated control group.There is no systematic difference in the change of body weight, food assumption, and amount of drinking water, between the irradiated group and the non-irradiated group, or between the recovered mice and the non-recovered mice. The survival was better in the irradiated group: the surviving fraction at the age of 90 weeks was 75 % in the irradiated group, while 50 % in the non-irradiated. Marked difference was also observed in the appearance of the coat hair, skin, and tail; better condition was kept in the irradiated group. These results suggest that the low dose irradiation modified the condition of the diabetic mice, which lead not only to the recovery of the diabetes, but also to the suppression of aging process.

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