報告書番号

U99067

タイトル（和文）

商用周波磁界と免疫系（その４） --350μTrms 回転円磁界の24週間曝露が白血病マウスのサイトカイン産生に与える影響--

タイトル（英文）

Power frequency magnetic field and immunologic system IV.Effects of 350μTrms circularly polarized, magnetic field exposure for 24 weeks on cytokine levels in leukemic mice

概要 （図表や脚注は「報告書全文」に掲載しております）

磁界影響として一部の疫学調査で白血病増加が示唆されているため，白血病を高率に自然発生するAKRマウス，計104匹を用い，5週齢から24週間，50 Hz，350μTrmsの回転円磁界を曝露した．曝露後，血清と脾臓で8種類のサイトカインとタンパク質量を測定し，血液学的，解剖学的，ならびに病理組織学的検査を盲検法で実施した．実験では，曝露群，対照群の他に比較飼育群を設け，各サイトカインとタンパク質量，ならびに各検査結果からスコア化した個体の白血病進行度に群間で統計学的な有意差が生じるかどうかを調べた．曝露群では脾臓のTNF-α，IL-6などが対照群と比べて減少傾向を示し白血病の進行も遅かったが，比較飼育群とは同程度で，いずれの群間にも有意差はなかった．これらの結果から，24週間の磁界曝露はサイトカイン量に変化を与えないことが明らかになった．今後は，時間経過を考慮した実験を実施する．

概要 （英文）

Based on a suggestive association between magnetic field (MF) exposure and increased risk of leukemia in epidemiology, we exposed AKR/J female mice, which spontaneously develop lymphatic leukemia, to 50 Hz, 350μTrms, circularly polarized MF for 24 weeks from 5 weeks of age. A total of 104 animals was assigned to either MF-exposed, control (sham-exposed), or comparative (facility-control) group. Experiment was conducted in a blind fashion. At the termination of exposure mice were sacrificed and amounts of eight cytokines (IL-1β, IL-3, IL-4, IL-6, IL-10, GM-CSF, IFN-γ, and TNF-α) and protein in sera and spleens were measured. Organ weight measurements, hematological examination, gloss pathological examination, and histopathological examination were also conducted. Group differences in amounts of cytokines and protein as well as an individual degree of leukemia, based on the results of these examinations, were statistically evaluated. Levels of spleen protein, IL-6, TNF-α, and some other cytokines in exposed group tended to be less than these in control group. Retardation of leukemia development in exposed group was also suggestive, however the tendency disappeared in comparison with comparative group. Non of these changes was statistically significant among three groups. These results indicated that MF exposure did not affect the amounts of cytokines in exposed AKR mice under conditions examined. Another time course study is on the way to reproduced this absence of MF effects on cytokine productions in the mouse model that spontaneously develops leukemia.

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