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

[FL細胞での50 Hz磁界の抗アポトーシス効果をミトコンドリアROS放出とそれに続くAkt活性化が潜在的に媒介する] med./bio.

Mitochondrial ROS Release and Subsequent Akt Activation Potentially Mediated the Anti-Apoptotic Effect of a 50-Hz Magnetic Field on FL Cells.

掲載誌: Cell Physiol Biochem 2016; 38 (6): 2489-2499

この研究は、ヒト羊膜由来FL細胞にさまざまな強度およびばく露時間で50Hz磁界MF)のばく露を与え、それに続いて一部の細胞はスタウロスポリンアポトーシス誘導剤)を添加して4時間培養し、MFばく露後のものについてはアポトーシス初期段階、細胞生存力に係わるミトコンドリアROSリン酸化Aktレベルを、MFばく露後にスタウロスポリンを加えて培養したものについては、アポトーシス初期段階を評価した。その結果、MFばく露は、スタウロスポリン誘発によるアポトーシス初期段階への防護作用を示し、この防護作用はミトコンドリア膜透過性遷移現象(mPT)阻害剤により消失した;MFばく露単独の場合、アポトーシス初期段階や細胞生存力に対し有意な影響を示さなかった;またMFばく露は、ミトコンドリアROSのレベルを上昇させ、そのROSはmPT細孔を通って細胞質へ放出され、ROS依存的なAktリン酸化を引き起こした;MFばく露の抗アポトーシス効果は、Aktを阻害すると完全に消失した、と報告している。

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研究目的(著者による)

The effects of exposure of human amniotic cells to a 50 Hz magnetic field on apoptosis and mitochondrial reactive oxygen species and the role of mitochondrial permeability transition (MPT) should be investigated.

詳細情報

MPT is defined as an increase in the permeability of the mitochondrial membranes for small molecules via opening of so called MPT pores. In a previous study by the authors (Feng et al. 2016), it was found that exposing human amniotic cells to a 50 Hz magnetic field induced an increase in intracellular reactive oxygen species (ROS) that in turn caused MPT. The study investigated the biological implications of this result, suspecting an anti-apoptotic effect.
Cells were exposed to a 0.4 mT magnetic field for up to 2 hours and were cultivated for up to 36 hours afterwards. In some approaches, cells were pretreated Bongkrekic acid, SB216763, cyclosporine A (inhibitors of MPT), acetylcysteine (ROS scavenger) or LY294002 (inhibitor of the PI3K/Akt signaling pathway) and/or treated with staurosporine (0,1 µM for 4 h) afterwards, to induce early apoptosis. Moreover, cells were exposed to a 0.2, 1 or 2 mT magnetic field for 60 min and treated with staurosporine afterwards. For each exposure, a separate sham exposure was used.
Positive controls were used.

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 for 5, 15, 30, 60 or 120 min
ばく露2: 50 Hz
ばく露時間: continuous for 60 minutes
ばく露3: 50 Hz
ばく露時間: continuous for 60 minutes
ばく露4: 50 Hz
ばく露時間: continuous for 60 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 for 5, 15, 30, 60 or 120 min
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 incubator with 95% air humidity and 5% CO2; the temperature was kept at 37.0 ± 0.1°C
ばく露装置の詳細 each chamber contained a set of square Helmholtz coils (20 cm Œ 20 cm), which were double-wrapped with two lines of copper wire and encased by mu-metal to shield cells from stray fields; a fan in the wall made air and temperature uniform between chambers and incubator; 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 one chamber was used for sham exposure with opposite direction currents fed into the coils; exposure and the corresponding sham exposure was conducted simultaneously
パラメータ
測定量 種別 Method Mass 備考
磁束密度 0.4 mT effective value 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 60 minutes
ばく露装置
ばく露の発生源/構造
  • E1と同じ装置
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 0.2 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 60 minutes
ばく露装置
ばく露の発生源/構造
  • E1と同じ装置
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 - 測定値 - -

ばく露4

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 60 minutes
ばく露装置
ばく露の発生源/構造
  • E1と同じ装置
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 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)

Exposure to a magnetic field alone had no significant effect on cell viability or early apoptosis compared to the sham exposure conditions. However, exposure to a magnetic field of 0.4 mT or 1 mT for 1 hour significantly reduced early apoptosis induced by staurosporine compared to sham exposed cells. As other magnetic flux densities or exposure durations did not show such an effect, the authors assumed an window effect for exposure duration (1 h) and intensity (0.4 mT to 1 mT).
In cells treated with the MPT inhibitor cyclosporine A and exposed to a 0.4 mT magnetic field for 1 hour, the mitochondrial reactive oxygen species level was significantly increased in comparison to cells only treated with the inhibitor, indicating that magnetic field-induced ROS are released into the cytoplasm via MPT. Treatment with MPT inhibitors Bongkrekic acid, SB216763, cyclosporine A or the ROS scavenger acetylcysteine significantly decreased the anti-apoptotic effect of the magnetic field, suggesting a relation between ROS release and the anti-apoptotic effect of the magnetic field.
Finally, the protein expression of phosphorylated protein kinase B was found to be significantly increased after exposure to the 0.4 mT magnetic field for 60 minutes compared to the sham exposure, but not when combined with MPT inhibitors or ROS scavengers.
The authors conclude that exposure of human amniotic cells to a 50 Hz magnetic field might have an anti-apoptotic effect via mitochondrial reactive oxygen species release through mitochondrial permeability transition and subsequent activation of the PI3K/Akt pathway.

研究の種別:

研究助成

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