研究のタイプ: 医学/生物学の研究 (experimental study)

[電離放射線、過酸化水素、c-Mycの過剰発現と組合せた60Hz電磁界ばく露後にDNA損傷なし] med./bio.

Absence of DNA damage after 60-Hz electromagnetic field exposure combined with ionizing radiation, hydrogen peroxide, or c-Myc overexpression

掲載誌: Radiat Environ Biophys 2014; 53 (1): 93-101

この研究は、60Hz磁界の単独ばく露または種々の外的要因との組合せばく露による正常な細胞系統のDNA損傷をコメットアッセイで調べた。マウスの線維芽細胞NIH3T3、ヒト肺線維芽細胞WI-38、ヒト肺上皮細胞L132、ヒト乳腺上皮細胞MCF10Aに、60Hz、1mTの一様磁界を単独あるいは外的要因と組み合わせてばく露した。試験した外的要因は、電離放射線(IR, 1 Gy)、過酸化水素ペトリ皿への添加、c-Mycの形質導入である。外的要因ばく露後に磁界ばく露(4または16時間)、または磁界ばく露(16時間)中に外的要因ばく露の2条件で実験した。その結果、磁界単独ばく露群では無ばく露群との有意差はなかった;3つの外的要因との組合せばく露のいずれの条件においても、相助的または加算的な影響は観察されなかった、と報告している。

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研究目的(著者による)

To investigate whether exposure to a 60 Hz-magnetic field alone or in combination with ionizing radiation, hydrogen peroxide or c-Myc overexpression induces a DNA damage in different cell lines.

詳細情報

In a previous study, the authors showed that magnetic field exposure alone or in combination with ionizing radiation, hydrogen peroxide or c-Myc overexpression did not increase the number of micronuclei and therefore did not induce a chromosomal damage (Jin et al. 2012 ). To test whether these treatments induce a primary DNA damage, in this study the comet assay was performed.
Different experiments were performed: 1.) magnetic field exposure or sham exposure, 2.) magnetic field exposure + ionizing radiation (1 Gy), 3.) magnetic field exposure + hydrogen peroxide (50 µM) and 4.) magnetic field exposure + c-Myc overexpression.
For c-Myc overexpression, cells were transfected with a c-Myc-containing vector or with an empty vector.
Exposure to the magnetic field was performed before or after the other treatments.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 60 Hz
ばく露時間: continuous for 4 or 16 hours

General information

Different experiments were performed: 1.) magnetic field exposure or sham exposure, 2.) magnetic field exposure + ionizing radiation (1 Gy), 3.) magnetic field exposure + hydrogen peroxide (50 µM) and 4.) magnetic field exposure + c-Myc overexpression.

ばく露1

主たる特性
周波数 60 Hz
タイプ
  • magnetic field
ばく露時間 continuous for 4 or 16 hours
ばく露装置
ばく露の発生源/構造
ばく露装置の詳細 a Merrit coil configuration consisting of four square coils (26 turns in the outer coils and 11 turns in the inner coils) was used; conducting wire of the coils had a diameter of 0.0014 mm; incubator consisted of three floors (upper, middle, bottom); temperature was maintained at 37 ± 0.3 °C; cells in 60-mm petri dishes were placed in the center of the floors; spatial variation of the magnetic field was less than 3%; magnetic field shielding system (made from ferrite material) was adopted to block strong magnetic fields from outside
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
磁束密度 1 mT - 計算値 - at the center of the incubator

ばく露を受けた生物:

方法 影響評価項目/測定パラメータ/方法

研究対象とした生物試料:
調査の時期:
  • ばく露後

研究の主なアウトカム(著者による)

In the first experiment, no significant differences were observed between exposed and sham exposed cell cultures. Moreover, no synergistic effects were observed when magnetic field exposure was combined with ionizing radiation, hydrogen peroxide, or overexpression of c-Myc.
The data confirm the results of the previous study: Exposure to a 60 Hz-magnetic field alone and in combination with ionizing radiation, hydrogen peroxide or c-Myc overexpression did not induce a primary DNA damage in different cell lines.

研究の種別:

研究助成

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