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

[肝がん細胞の増殖と分化における50 Hz磁界とメラトニンの拮抗作用] med./bio.

Antagonistic effects of a 50 Hz magnetic field and melatonin in the proliferation and differentiation of hepatocarcinoma cells.

掲載誌: Cell Physiol Biochem 2012; 30 (6): 1502-1516

この研究は、50Hz、10μTの磁界への間欠ばく露に対するヒト肝がん由来HepG2細胞の応答を、生理学的用量(10nM)または薬理学的用量(1μM)のメラトニン有無の条件下で調べた。その結果、磁界ばく露群では有意な増殖作用および脱分化作用が生じたが、これは10nMのメラトニンによって防止された;逆に、メラトニン投与はHepG2細胞増殖抑制作用および分化作用を生じるが、これは磁界への同時ばく露によって消失した、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 hepatic carcinoma cells to a 50 Hz magnetic field and a treatment with melatonin on cell viability, proliferation and differentiation should be investigated.

詳細情報

Cells were exposed with or without melatonin (10 nM or 1 µM). For each group, a respective sham exposure was conducted. Cells were investigated directly after exposure.
Additionally, cells were treated with melatonin alone (0.01 nM - 1 µM), without exposure to the magnetic field or sham exposure. Cells of these groups were investigated 5 days after plating.

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: intermittent exposure (3 h on/3 h off) for 24 hours
ばく露2: 50 Hz
ばく露時間: intermittent exposure (3 h on/3 h off) for 42 hours
ばく露3: 50 Hz
ばく露時間: intermittent exposure (3 h on/3 h off) for 90 hours

ばく露1

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
偏波
  • linear
ばく露時間 intermittent exposure (3 h on/3 h off) for 24 hours
Modulation
Modulation type cf. additional information
ばく露装置
ばく露の発生源/構造
チャンバの詳細 60 mm petri dishes in two identical, magnetically shielded chambers (Co-NETIC metal) located in two identical CO2 incubators
ばく露装置の詳細 two identical pairs of coils connected in series to produce a vertically polarized and homogeneous magnetic field were placed inside the shielded chambers; each coil was made of 1000 turns of enameled copper wire; petri dishes were placed in the center of the coils; the incubator maintained a 5% CO2 and 100% humidity atmosphere at 37°C
Sham exposure A sham exposure was conducted.
Additional information in each experimental run, only one of the two coil sets was energized for MF exposure and the other one was used for sham exposure; both incubators were used alternatively for MF-exposure or sham exposure, in a random sequence
パラメータ
測定量 種別 Method Mass 備考
磁束密度 10 µT - 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
偏波
  • linear
ばく露時間 intermittent exposure (3 h on/3 h off) for 42 hours
Modulation
Modulation type cf. additional information
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 µT - 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
偏波
  • linear
ばく露時間 intermittent exposure (3 h on/3 h off) for 90 hours
Modulation
Modulation type cf. additional information
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 µT - 測定値 - -

Reference articles

  • Trillo MA et al. (2012): [ヒトがん細胞株の増殖に対する50Hz磁界及びオールトランスレチノールの影響力]

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:
  • ばく露後

研究の主なアウトカム(著者による)

The cell viability did not show any significant differences between any exposure or melatonin-treated group and the respective sham exposure or control groups.
However, exposure to the magnetic field alone resulted ina significantly increased cell proliferation and a significantly decreased differentiation compared to the sham exposure groups.
A treatment with a very low dose of melatonin (0.01 nM) resulted in a significantly increased cell proliferation as well, higher concentrations (0.2 nM - 1 µM) led to a significantly decreased proliferation and a significantly increased differentiation (10 nM and 1 µM) compared to the control group.
In the co-exposure groups, melatonin (10 nM and 1 µM) led to a significant reduction or even a suppression of the proliferation-promotive effect of the magnetic field exposure. Regarding differentiation, however, only a small dose of melatonin (10 nM) reversed the decreased differentiation effect of the magnetic field exposure. Higher concentrations of melatonin in combination with the magnetic field (1 µM) did not show this antagonistic effect and led instead to the same decreased differentiating effects as found in the magnetic exposure alone.
The authors conclude, that exposure to a 50 Hz magnetic field and a treatment with melatonin might have partially antagonistic effects on cell proliferation and differentiation in hepatic carcinoma cells. As a whole, the results suggest that weak extremely low frequency magnetic fields could influence cancer-related processes in vitro, and reinforce the hypothesis that these fields could interfere with the potentially anti-tumoral action of melatonin.

研究の種別:

研究助成

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