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

[日周リズム関連遺伝子の発現と超低周波磁界] med./bio.

Circadian gene expression and extremely low-frequency magnetic fields: An in vitro study.

掲載誌: Bioelectromagnetics 2015; 36 (4): 294-301

この研究は、ヒト線維芽細胞株の日周時計遺伝子に対する超低周波(ELF)磁界の影響を調査した。その結果、ELF磁界(0.1mT、50Hz)ばく露は時計遺伝子BMAL1、PER2、PER3、CRY1、CRY2の発現同期させ得ることを見出した。また、ELF磁界ばく露血清ショック刺激によって先に同期した日周時計遺伝子発現の変化を生じた。著者らは、これらの結果は、ELF磁界末梢の時計遺伝子発現変調させることで、日周生理学的プロセスを誘導し得るかも知れないという仮説を支持している、と結論付けている。

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研究目的(著者による)

It should be investigated if exposure of human dermal fibroblasts to a 50 Hz magnetic field can induce a circadian gene expression or modulate an existing circadian gene expression pattern.

詳細情報

The presence of a molecular clock maintaining a circadian rhythm in cells is known. This intracellular clock is regulated by so-called "clock genes". The set of clock genes investigated in this study is inactive under nutrient defiency conditions, but the circadian gene expression can be induced by the addition of nutrients ("serum shock stimulation"). However, also other stimuli, such as magnetic fields, could affect this intracellular clock.
Cells were divided into the following groups: 1) exposure of nutrient-limited cells to the magnetic field for 1 h and afterwards observation for 47 h, 2) induction of circadian gene expression by serum shock stimulation and afterwards exposure to the magnetic field and observation for 48 h. For each group, a corresponding sham exposure was conducted.
Each experiment was repeated three times with 3 replicates, respectively.

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 1 hour
ばく露2: 50 Hz
ばく露時間: continuous for up to 48 hours

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 1 hour
ばく露装置
ばく露の発生源/構造
チャンバの詳細 culture flask
ばく露装置の詳細 the coil consisted of a ferromagnetic core with a cross section of 4 x 5 cm2 equipped with two windings (550 turns each) connected in series, which were inserted around the lateral columns; in the middle of the central column, there was a 4 cm air gap for the culture flasks; magnetic flux orientation was orthogonal to the culture flask; exposure unit was positioned into a water-jacked temperature and atmosphere regulated incubator (37.0 ± 0.1°C and 5% CO2)
Sham exposure A sham exposure was conducted.
Additional information electric resistors in sham exposure incubator produced an average magnetic flux density of 5 µT
パラメータ
測定量 種別 Method Mass 備考
磁束密度 0.1 mT - 計算値 - -
電界強度 0.157 mV/m maximum 推定値 - -

ばく露2

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
ばく露時間 continuous for up to 48 hours
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 0.1 mT - 計算値 - -
電界強度 0.157 mV/m maximum 推定値 - -

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)

A significant circadian gene expression pattern with a robust 24 h oscillation in all genes investigated could be induced in nutrient-limited cells exposed to the magnetic field (group 1) in contrast to the corresponding sham exposed cells.
Both, cells exposed after serum shock (group 2) and the corresponding sham exposed cells showed a circadian, oscillating gene expression pattern in all genes investigated after serum shock, but cells exposed to the magnetic field showed a significant up-regulation of the gene expression rates of all genes over time in comparison to the corresponding sham exposed cells. However, the oscillation in principle pattern was not altered by the magnetic field.
The authors conclude that exposure of human dermal fibroblasts to a 50 Hz magnetic field could induce a circadian gene expression and modulate an existing circadian gene expression pattern.

研究の種別:

研究助成

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