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

[NADPHオキシダーゼが産生するスーパーオキシドは50Hz磁界による上皮成長因子受容体のクラスタリングを媒介する] med./bio.

NADPH oxidase-produced superoxide mediated a 50-Hz magnetic field-induced epidermal growth factor receptor clustering.

掲載誌: Int J Radiat Biol 2016; 92 (10): 596-602

この研究は、著者が先行論文で報告した知見である「50Hz磁界による上皮成長因子受容体(EGFR)のクラスタリング」の分子レベルでのメカニズムをヒト羊膜上皮細胞(FL)で実験的に検討した。磁界レベルとばく露時間を変え、活性酸素種ROS)、細胞質およびミトコンドリアでのスーパーオキシド産生、EGFRクラスタリングを分析した。その結果、0.2mT以上への15分間ばく露は総ROS産生を増加させた;0.4 mTでは、5、15、30分間 のいずれのばく露後でも総ROS産生と細胞質スーパーオキシド産生が増加したが、ミトコンドリアでのスーパーオキシド産生は15、30分間 のばく露後でのみ見られた;Nox阻害剤の事前処置により、磁界による細胞質スーパーオキシド産生とそれに続くEGFRクラスタリングは効果的に抑制されたが、ミトコンドリアでのスーパーオキシド産生は影響を受けなかった、と報告している。

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研究目的(著者による)

The mechanisms of action of 50 Hz magnetic field-induced of epidermal growth factor receptor clustering in human amniotic epithelial cells should be investigated.

詳細情報

In previous studies (Sun et al. 2004, Sun et al. 2008), the authors found that exposure to a magnetic field could induce epidermal growth factor receptor (EGFR) clustering in cultured cells. These data suggested that EGFR is one of the likely targets of magnetic fields on cell membrane. In a further study, Park et al. (2013) found that clustering might be mediated by reactive oxygen species. However, the source of reactive oxygen species production remained unclear.
Cells were divided into the following groups: exposure to a 0.4 mT magnetic field for 1) 5 minutes, 2) 15 minutes, 3) 30 minutes or 4) 60 minutes and exposure to a magnetic field of 5) 0.1 mT or 6) 0.2 mT for 15 minutes and 7) sham exposure.
Positive control was conducted.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 50 Hz
ばく露時間: continuous for 5, 15, 30 or 60 minutes
ばく露2: 50 Hz
ばく露時間: continuous for 15 minutes
ばく露3: 50 Hz
ばく露時間: continuous for 15 minutes

ばく露1

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 continuous for 5, 15, 30 or 60 minutes
ばく露装置
ばく露の発生源/構造
チャンバの詳細 two exposure chambers in CO2 incubator (95% humidity and 5% CO2)
ばく露装置の詳細 each chamber contained a set of square Helmholtz coils (20 cm x 20 cm), which were double-wrapped with two lines of copper wire, and was encased by mu-metal; a fan on the wall ventilated and maintained air and temperature uniformity between chamber and incubator; temperature in the chambers was maintained at 37.0 ± 0.1°C throughout the entire exposure period; cell dishes were put in the center of the coils; the magnetic field was perpendicular to the dishes
Sham exposure A sham exposure was conducted.
Additional information current was fed into the coils with the same direction in the exposure chamber, whereas opposite direction currents were fed into the coils in the sham exposure chamber; difference in temperature between exposure and sham exposure conditions did not exceed 0.1°C
パラメータ
測定量 種別 Method Mass 備考
磁束密度 0.4 mT - 測定値 - -

ばく露2

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 continuous for 15 minutes
ばく露装置
ばく露の発生源/構造
  • E1と同じ装置
パラメータ
測定量 種別 Method Mass 備考
磁束密度 0.1 mT - 測定値 - -

ばく露3

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 continuous for 15 minutes
ばく露装置
ばく露の発生源/構造
  • E1と同じ装置
パラメータ
測定量 種別 Method Mass 備考
磁束密度 0.2 mT - 測定値 - -

Reference articles

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:
  • ばく露中
  • ばく露後

研究の主なアウトカム(著者による)

The total reactive oxygen species production was significantly increased in groups 1, 2, 3 and 6 compared to the sham exposure group, with the most distinct increase in group 2 (0.4 mT). Groups 5 and 6 were not regarded in further tests.
Cytoplasmic reactive oxygen species production was significantly increased in groups 1-3 compared to the sham exposure group. To examine the NADPH oxidase as a potential source of reactive oxygen species, these groups were also tested with addition of the NADPH oxidase inhibitor diphenylene iodonium. These co-exposed cells showed a significantly reduced cytoplasmic reactive oxygen species production compared to cells exposed to the magnetic field alone, comparable to sham exposure level.
Mitochondrial reactive oxygen species production was significantly increased in groups 2 and 3 compared to sham exposed cells, however, treatment with the NADPH oxidase inhibitor had no significant effect.
Confocal microscopy showed EGFR clustering was significantly higher in group 2 compared to the sham exposure group. However, pretreatment with the NADPH oxidase inhibitor completely inhibited MF-induced EGFR clustering.
The authors conclude that the NADPH oxidase might mediate the 50 Hz magnetic field-induced epidermal growth factor receptor clustering in human amniotic epithelial cells via superoxide production.

研究の種別:

研究助成

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