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

[電磁界ばく露は細胞内CaおよびROS低下による酸素-グルコース欠乏性ミクログリア細胞死を減少させる] med./bio.

Exposure to electromagnetic field attenuates oxygen-glucose deprivation-induced microglial cell death by reducing intracellular Ca(2+) and ROS.

掲載誌: Int J Radiat Biol 2016; 92 (4): 195-201

この研究は、イン・ビトロのヒト・ミクログリア細胞株HMO6に酸素グルコース欠乏(OGD)により誘導される虚血細胞死に対し、電磁界(10、50、100Hzでの1 mTまたは50 Hzでの0.01、0.1、1 mT)ばく露が保護効果を示すか否かを調べた。評価項目は細胞生存力細胞内カルシウムレベル、活性酸素種ROS)レベルである。その結果、50 Hz/1 mTのばく露がOGD誘導性の細胞内カルシウムおよびROSのレベル上昇を阻害することにより、OGD誘導細胞死からHMO6細胞株を保護することが示された、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 ischemic human microglial cells to a 50 Hz magnetic field on the cell survival rate, intracellular calcium and reactive oxygen species should be investigated.

詳細情報

Neurotoxic effects of hypoxic-ischemia are thought to be mainly caused by calcium overload and production of reactive oxygen species, ultimately resulting in cell death. It is suggested that microglia contribute to the protection of the brain against ischemic injury. Hence, their preservation in case of ischemia might be of therapeutic use.
Ischemic conditions were experimentally induced via oxygen and glucose deprivation (OGD) in a special culture medium without glucose and in an incubator with little oxygen. Cells were divided into the following groups: 1) exposure to 10 Hz/1 mT, 2) exposure to 50 Hz/1 mT, 3) exposure to 100 Hz/1 mT, 4) exposure to 50 Hz/0.01 mT, 5) exposure to 50 Hz/0.1 mT, 6) OGD treatment alone, 7) OGD treatment and exposure to 50 Hz/1 mT, 8) no OGD treatment and no exposure (control group). Except for test on cell survival with all groups, only groups 6, 7 and 8 were used. Groups 1-5 were used to determine the optimum frequency and magnetic flux density of exposure for the most potent protection against OGD-induced cell death (remark EMF-Portal: however, there are no specifications on the use of OGD in these groups).

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 10 Hz
ばく露時間: continuous for 4 hours
ばく露2: 50 Hz
ばく露時間: continuous for 4 hours
ばく露3: 100 Hz
ばく露時間: continuous for 4 hours
ばく露4: 50 Hz
ばく露時間: continuous for 4 hours
ばく露5: 50 Hz
ばく露時間: continuous for 4 hours

ばく露1

主たる特性
周波数 10 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 continuous for 4 hours
ばく露装置
ばく露の発生源/構造
チャンバの詳細 cell culture dishes in gas incubator with 94% N2, 1% O2, and 5% CO2
ばく露装置の詳細 exposure system consisted of two identical coils to generate the uniform vertical magnetic field; diameter of coils = 15 cm (inner) and 26 cm (outer); thickness of coils = 7.5 cm; distance between coils = 18 cm; wire diameter = 18 AWG; number of loops = 1000; the system was placed in the center of a gas addition incubator; cell culture dishes were maintained at the center of the uniform field area; a thermometric probe placed inside and outside the EMF generator revealed no significant temperature difference between culture media of exposed or unexposed cells
パラメータ
測定量 種別 Method Mass 備考
磁束密度 1 mT - - - -

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 4 hours
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 1 mT - - - -

ばく露3

主たる特性
周波数 100 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 continuous for 4 hours
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 1 mT - - - -

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 4 hours
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 0.01 mT - - - -

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 continuous for 4 hours
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 - - - -

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:
  • ばく露前
  • 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 pretests, group 2 (50 Hz/1 mT) showed the largest and significant increase in cell survival compared to the control group (group 8).Therefore, the authors suggested 50 Hz/1 mT as the optimum field for protection against cell death and used it in the subsequent tests.
Ischemia evoked by OGD treatment with or without exposure to the 50 Hz/1 mT magnetic field (groups 6 and 7) significantly reduced the cell survival compared to the control group. However, OGD treatment and exposure to the magnetic field (group 7) showed a significantly higher cell survival compared to OGD treatment alone (group 6).
The calcium level was significantly increased after 30 minutes of exposure in group 6 compared to the initial value and returned to the initial value after 60 minutes, while the calcium level in group 7 was significantly reduced compared to group 6 during the whole exposure.
The level of reactive oxygen species was significantly increased in group 6 compared to group 7 and the control group and it was found that only xanthine oxidase was involved in OGD-induced cell death.
The authors conclude that exposure to a 50 Hz magnetic field might protect human microglial cells from ischemia-induced cell death by reducing the intracellular calcium and ROS levels. The xanthine oxidase might be one of the main mediators of the ischemia-induced cell death. Magnetic field exposure could be clinically useful to attenuate hypoxic-ischemic brain injury.

研究の種別:

研究助成

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