報告書番号

U00035

タイトル（和文）

商用周波磁界と免疫系（その６） -－磁界曝露により生じる誘導電流が細胞内活性酸素産生に及ぼす影響－-

タイトル（英文）

Power frequency magnetic fields and immunologic system (Part 6)-Effects of magnetically induced current on the production of intracellular reactive oxygen radicals.-

概要 （図表や脚注は「報告書全文」に掲載しております）

磁界曝露により生じる誘導電流がマクロファージの活性酸素産生機能に影響を及ぼすか否かを検討した。同一磁束密度下で誘導電流密度の異なる培養条件を設けるため、培養液中の誘導電流密度が最大約500 mA/m2発生するリング状培養容器を開発し、予め一定濃度の細胞を付着させたチャンバースライドをその培養容器に移す実験手法を確立した。細胞に活性酸素を産生させる刺激物質としてPMAを用いて円状およびリング状培養容器内で50 Hz、10 mT垂直磁界に30分間曝露し、細胞内活性酸素量をフローサイトメトリー法により測定した。対照群と統計学的に比較した結果、磁界強度、ならびに誘導電流密度の異なる群間のいずれの曝露条件下でも細胞内活性酸素量に有意な差はなく、その結果は4回の繰り返し実験で再現された。一連の実験により、マクロファージの活性酸素産生能は、磁界および誘導電流に影響されないことが明らかとなった。

概要 （英文）

Some studies have suggested that magnetic fields (MF) may increase the concentration of free radicals from immune cells stimulated with phorbol 12-myristate 13-acetate (PMA). Free radicals can react with proteins, lipids and DNA resulting in cell damage and transformation, but they play an important role in the maintenance of physiological homeostasis. Free radicals production is the primary function of macrophages and neutrophils leading to the formation of reactive oxygen species (ROS). Recently, magnetically induced current in the body has been suggested to be a possible mechanism causing biological effects. The aim of our study was to investigate the effect of magnetically induced current on the ROS production in mouse macrophages stimulated with PMA. We fabricated an o-shape culture plate that maximizes the induced current in culture medium. The value was about 500 mA/m2 when it was exposed to 50 Hz, 10 mTrms linearly polarized (vertical) MF. We established the culture methods using the plate and a chamber slide to minimize the cell number tested. Peritoneal macrophages stimulated with 1 μg/ml PMA were exposed to 50 Hz, 10 mTrms MF for 30 min (n=3 to 4). Sham-exposure was conducted simultaneously with an identical exposure system that was not energized. The intracellular ROS production was determined with flow cytometry using dichlorofluorescein diacetate (DCFH-DA) as an oxidative prove. Statistical comparison was performed between exposed group and corresponding sham-exposed group. Under each experiment condition, four replications were made. Experiments were carried out in a blind fashion. There were no significant changes due to MF in any experiments. In the exposed group, the ROS production of the cells cultured in the o-shape plate was similar to ones cultured in a small circle plate. There were also no significant differences in each culture plate between exposed and sham-exposed group. These results indicated that power frequency MF exposures and magnetically induced currents did not affect the ROS production under the conditions tested.

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