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

[マウスでの胚発生および胚性幹細胞での脈管形成に対する高および低強度磁界の影響の違い] med./bio.

Differential effects of high and low strength magnetic fields on mouse embryonic development and vasculogenesis of embryonic stem cells.

掲載誌: Reprod Toxicol 2016; 65: 46-58

この研究は、磁界(MFs:50Hz正弦波磁界AC)または静磁界(DC))の強度の違い(10mTおよび1mT)による影響の違いを、(1)妊娠マウスの20日間ばく露による胚発生への影響、(2)マウス胚性幹細胞(ES細胞)由来の胚様細胞塊(EB)へのばく露の影響について調べた。その結果、妊娠中の10mT MFsばく露により、胚の吸収消失および胚死亡の増加、頭殿長および体重の減少、血管分化の低下、組織学的変化、血管内皮増殖因子(VEGF)タンパク質発現の消失が見られた;ES細胞由来EBへの10mT MFsばく露により、活性酸素種ROS)増加、血管マーカおよびVEGF発現の低下、アポトーシス増加が見られた、と報告している。(JEIC注:アブストラクトでの結果の記述において、MFsがACかDCかは明示されていない)

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研究目的(著者による)

The effects of prenatal exposure of mice to a static or 50 Hz magnetic field on the embryonic development should be investigated.

詳細情報

The study comprised an in vivo and an in vitro part. For the in vivo part, pregnant mice were divided into the following groups (n=10 for each method and time of investigation, total number unclear): exposure to a 1) 1 mT 50 Hz magnetic field, 2) 1 mT static magnetic field, 3) 10 mT 50 Hz magnetic field, 4) 10 mT static magnetic field and 5) sham exposure. Embryos were collected and examined after 5, 8, 12 and 20 days of exposure.
In addition, 50 non-pregnant mice were exposed to the same fields (n=10 each) but no detailed results were shown.
For the in vitro part, embryoid bodies, aggregations of pluripotent mouse embryonic stem cells, were used as models for embryonic development and were exposed to the same fields: 6) 1 mT 50 Hz magnetic field, 7) 1 mT static magnetic field, 8) 10 mT 50 Hz magnetic field, 9) 10 mT static magnetic field and 10) sham exposure.
In the in vitro tests, cells were also treated with p38 MAPK, JNK and ERK-1/2 inhibitors and free radical scavengers to examine the signal pathways.

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: 8 hours/day for up to 20 days during gestation
in vivo
ばく露2:
  • DC/static
ばく露時間: 8 hours/day for up to 20 days during gestation
in vivo
ばく露3: 50 Hz
ばく露時間: 8 hours/day for up to 20 days during gestation
in vivo
ばく露4:
  • DC/static
ばく露時間: 8 hours/day for up to 20 days during gestation
in vivo
ばく露5: 50 Hz
ばく露時間: 8 hours/day from 2 to 8 during differentiation
in vitro
ばく露6:
  • DC/static
ばく露時間: 8 hours/day from 2 to 8 during differentiation
in vitro
ばく露7: 50 Hz
ばく露時間: 8 hours/day from 2 to 8 during differentiation
in vitro
ばく露8:
  • DC/static
ばく露時間: 8 hours/day from 2 to 8 during differentiation
in vitro

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 8 hours/day for up to 20 days during gestation
Additional information in vivo
ばく露装置
ばく露の発生源/構造
チャンバの詳細 high enough cages made of dielectric, transparent plastic
ばく露装置の詳細 ten mice were placed in 2 cages (5 mice per cage) in homogeneous field; coils were wound on tubes from polyvinylchloride (PVC), which shielded against emission of electric fields; temperature changes in exposure chamber was 1°C ± 0.5°C
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2

主たる特性
周波数
  • DC/static
タイプ
  • magnetic field
ばく露時間 8 hours/day for up to 20 days during gestation
Additional information in vivo
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3

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 8 hours/day for up to 20 days during gestation
Additional information in vivo
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 10 mT - 測定値 - -

ばく露4

主たる特性
周波数
  • DC/static
タイプ
  • magnetic field
ばく露時間 8 hours/day for up to 20 days during gestation
Additional information in vivo
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 10 mT - 測定値 - -

ばく露5

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 8 hours/day from 2 to 8 during differentiation
Additional information in vitro
ばく露装置
ばく露の発生源/構造
  • E1と同じ装置
ばく露装置の詳細 differences from exposure 1: embryoid bodies in petri dishes; 5% CO2, 37°C
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6

主たる特性
周波数
  • DC/static
タイプ
  • magnetic field
ばく露時間 8 hours/day from 2 to 8 during differentiation
Additional information in vitro
ばく露装置
ばく露の発生源/構造
  • same setup as exposure 5
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7

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 8 hours/day from 2 to 8 during differentiation
Additional information in vitro
ばく露装置
ばく露の発生源/構造
  • same setup as exposure 5
パラメータ
測定量 種別 Method Mass 備考
磁束密度 10 mT - 測定値 - -

ばく露8

主たる特性
周波数
  • DC/static
タイプ
  • magnetic field
ばく露時間 8 hours/day from 2 to 8 during differentiation
Additional information in vitro
ばく露装置
ばく露の発生源/構造
  • same setup as exposure 5
パラメータ
測定量 種別 Method Mass 備考
磁束密度 10 mT - 測定値 - -

Reference articles

  • Bekhite MM et al. (2010): [静的電磁界は活性酸素種が介在した血管内皮成長因子増加によりマウス胚性幹細胞に脈管形成および軟骨骨形成を誘導する]

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:
研究対象とした臓器系:
  • 生殖
  • liver, lung, eyes, ovary and uterus
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)

In the 10 mT static and 50 Hz magnetic field groups (groups 3 and 4), a significantly increased number of resorbed and dead fetuses, pronounced histological alterations, reduced blood vessel formation and a significantly reduced VEGF protein expression in all organs compared to the sham exposure group were found. Additionally, a significantly reduced crown-rump length and body weight of fetuses were found in group 4 compared to the sham exposure group after 20 days. This was not observed in 1 mT magnetic fields (groups 1 and 2) but instead, VEGF expression in the ovary was significantly increased compared to the sham exposure group.
In embryoid bodies, exposure to 10 mT static or 50 Hz fields (groups 8 and 9) significantly increased reactive oxygen species (6-fold increase) and apoptosis, while significantly decreasing the blood vessel formation and VEGF expression compared to the sham exposure group.
In groups 6 and 7 (exposure of embryoid bodies to 1 mT static or 50 Hz fields), reactive oxygen species were also significantly increased compared to the sham exposure group but only a 2-fold increase was measured, and the expression of VEGF was significantly increased.
Treatment with inhibitors showed that reactive oxygen species were involved in the magnetic field-induced signal transduction, which led to activation of VEGF.
The authors conclude that prenatal exposure of mice to high (10 mT) static or 50 Hz magnetic field might have adverse effects on the embryonic development. VEGF is possibly an important mediator in these effects.

研究の種別:

研究助成

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