報告書番号

U98041

タイトル（和文）

商用周波磁界と免疫系（その２） -1.4 ～ 350 μTrms の磁界に曝露した抗体刺激マウスのサイトカイン産生-

タイトル（英文）

Power frequency magnetic fields and immunologic system II.Effects of 1.4 to 350 μTrms magnetic field exposures on cytokine productions in mice stimulated with an antibody

概要 （図表や脚注は「報告書全文」に掲載しております）

研究目的は，免疫系の情報伝達物質（サイトカイン）の産生能が磁界で変化するか否かを解明することである．さまざまな磁界に曝露した2系統のマウスのTリンパ球を抗CD3ε抗体で刺激し，血清と脾臓で産生された5種類のサイトカイン（IFN-γ ，TNF-α ，IL-6 ，IL-4 ，IL-10 ）を定量した．無曝露でのベースラインに装置間の差がないことを確認したのちに，1群10～12匹のマウスに50 Hz，1.4, 70, 350 μTの回転円磁界，または250 μTの水平磁界を，3, 6, 12週間曝露した．測定したほとんどのサイトカインに曝露による変化はなかった．変化が見られた場合も磁界の曝露強度や曝露期間とは無関係で，再実験による変化の再現性もなかったことから，刺激したTリンパ球のサイトカイン産生に磁界は影響を与えないことが示唆された．今後は，Tリンパ球以外の免疫細胞に関して同様の曝露実験を実施する．

概要 （英文）

This report describes the possible magnetic field (MF) effect on production of cytokines, polypeptide hormones secreted from immune cells, that regulate a variety of immunological processes such as endotoxin shock and anti-tumor activity. We employed an experimental model of the enhanced immune function in vivo that is the production of endogenous cytokines from T-lymphocytes stimulated with an anti-CD3ε antibody. Objective is to examine if 50 Hz, 1.4 to 350 μTrms MF exposures for 3 to 12 weeks can alter the cytokine secretions in mice. Animals, 6 weeks of age, were specific pathogen free and housed in the MF exposure facilities that were barrier system. Groups of 10 to 12 inbred male C57BL/6, or outbred male ddY, in four identical exposure facilities were exposed to 0, 1.4, 70, or 350 μTrms, 50 Hz, circularly polarized (CP) or 250 μTrms horizontal of linearly polarized (LP) MF. Immediately after the exposure, mice were treated with an intra-venous injection of anti-CD3ε monoclonal antibody. Induced three cytokines, interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) in sera and spleens were measured with enzyme-linked immunosorbent assay. Other inhibitory cytokines, IL-4 and IL-10 in spleens, were also measured. Experiments were conducted in a blind fashion. Background 50 Hz MF was less than 0.02 μTrms. The multiple-square coils were composed of two orthogonal sets of 4-square bobbins; one set for vertical field and another for horizontal. Applied MFs were as uniform as less than 5% in the intensity variance. The geomagnetic field was 42.3 μT in the coils. Exposure was conducted over 22 hours a day, 7 days per week. Bases of these cytokine productions in both strains of mice were first determined without MF exposure in all four facilities for 6 weeks. No difference among facilities in either cytokine level in sera and spleens was evident. Thereafter, C57BL/6 were exposed to 1.4 or 350 μTrms CP-MF for 3 weeks, or 1.4, 70, 350 μTrms CP-MF or 250 μTrms LP-MF for 6 weeks. Decrease in serum IL-6 in 6 weeks, 350 μTrms CP-MF exposed group was the only one change statistically significant in comparisom with sham-exposed group. In addition, ddY were exposed to 70 or 350μTrms CP-MF or 250 μTrms LP-MF for 6 weeks; ddY were also exposed to 12 weeks of 350 μTrms CP-MF or 12 weeks of 350 μTrms CP-MF followed by one week of sham exposure. Serum TNF-α increased and spleen IL-6 decreased both in 70 μTrms CP-MF; all the rest of cytokines' levels measured, including IL-4, IL-10, and IFN-γ, did not alter with MF exposure. Observed changes, however, were not considered to be biologically significant, because directions of the changes were not constant, reproducibility of the changes was not manifest, and the changes were not exposure dose-related nor exposure time-dependent. Obtained data therefore suggest that the MF exposure did not affect the endogenous cytokine productions in mice under conditions examined.

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