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

[マウス胚線維芽細胞において電力周波数磁界が誘導した活性酸素種が関連する自食作用] med./bio.

Power frequency magnetic fields induced reactive oxygen species-related autophagy in mouse embryonic fibroblasts.

掲載誌: Int J Biochem Cell Biol 2014; 57: 108-114

この研究は、マウス胚線維芽細胞(MEF)の自食作用に対する電力周波数磁界(PFMF:50Hz、2mT、ばく露時間0.5、2、6、12、24時間)の影響を調べた。その結果、6時間ばく露で、自食作用マーカ有意な上昇が観察された、と報告している。

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研究目的(著者による)

The effects of acute in vitro exposures of mouse embryonic fibroblasts to a 50 Hz magnetic field on autophagy should be investigated, as it is important for cellular homeostasis.

詳細情報

Autophagy (also referred to as auto-phagocytosis) means the process in which cells digest cellular components. In the present paper, only macroautophagy was examined. Here, cell components are enclosed in a so called autophagosome in a first step. In a second step, the fusion with a lysosome starts the degradation. LC3 is a protein that is distributed ubiquitously in the cell. During autophagic processes, it concentrates in autophagosomes as LC3-II and gets degraded there. Both forms are common markers for autophagy. To ensure that an increase of LC3-II represents an actual increase of the autophagic flux and not a block of the fusion of autophagosome and lysosome for instance, tests with chloroquine were conducted. Chloroquine blocks the fusion and hence induces an increase of LC3-II without an increase of the autophagic flux.
Rapamycin was used as positive control for autophagy and the activity of the mTOR (mammalian target of rapamycin) pathway. Phosphorylated p70S6 kinase is a direct substrate of mTOR activity and a decrease is used as a common marker for mTOR activity. Positive controls were performed for flow cytometry and the TUNEL assay.

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 0.5, 2, 6, 12 and 24 h

ばく露1

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
ばく露時間 continuous for 0.5, 2, 6, 12 and 24 h
ばく露装置
ばく露の発生源/構造
チャンバの詳細 2 chambers were placed in one incubator with constant environmental conditions (37 °C, 5% CO2); each chamber was composed of a series of Helmholtz coils
ばく露装置の詳細 the connection of the coils in one chamber was in-phase to generate a magnetic field for exposure, whereas an opposite phase connection in the other chamber generated an offset magnetic field for sham exposure
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 - - - -

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)

Although an increase of autophagic markers could be observed at all times, only the 6-hour exposure showed a significant and consistent increase in autophagy in Western Blot, confocal laser scanning microscopy and transmission electron microscopy compared to sham exposure. The tests with chloroquine confirmed that this was the result of an actual increase of the autophagic flux. The mTOR pathway was inactive during these processes. Moreover, a significant higher level of reactive oxygen species could be found in the 6-hour exposure compared to sham exposure. The tests on apoptosis did not show any differences.
The authors conclude that an in vitro exposure of mouse embryonic fibroblasts to a 50 Hz magnetic field for 6 h causes a significant increase in autophagy, which might be related to a simultaneous increase in reactive oxygen species and works without an activation of the common autophagy signaling pathway involving mTOR.

研究の種別:

研究助成

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