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

[正弦波50Hz磁界への生涯ばく露および低線量γ線急性ばく露はSprague-Dawleyラットに発がん作用を引き起こす] med./bio.

Life-span exposure to sinusoidal-50 Hz magnetic field and acute low-dose gamma radiation induce carcinogenic effects in Sprague-Dawley rats.

掲載誌: Int J Radiat Biol 2016; 92 (4): 202-214

この研究は、成獣の雌雄のSDラットに、正弦波50Hz磁界(S-50Hz MF:20または1000μT)への生涯ばく露(出生前から自然の死まで)および低線量γ線(0.1 Gy)の急性単回ばく露(6週齢)を組み合わせて与え、その発がん作用を調べた。その結果、雄および雌のラットの乳線への有意な発がん作用、雄ラットでの心臓の悪性神経鞘腫発症率の有意な上昇およびリンパ腫白血病発生率上昇が示された、と報告している。

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研究目的(著者による)

The carcinogenic effects of prenatal and postnatal exposure of rats to a 50 Hz magnetic field in combination with gamma radiation should be investigated in a life-span study.

詳細情報

The present study is part of a large EMF animal test project, which has already been described by Soffritti et al. 2010.
A total of 1658 pregnant rats was divided into 3 groups (remark EMF-Portal: number of rats in each group is not stated): exposure to a magnetic field of 20 µT, exposure to a magnetic field of 1000 µT, control group without any exposure. The newborn rats were further exposed and divided into the following groups: 1) exposure to a magnetic field of 20 µT and treatment with gamma radiation (105 male, 107 female rats), 2) exposure to a magnetic field of 1000 µT and gamma radiation (110 male, 112 female rats), 3) only gamma radiation (118 male, 105 female rats), 4) control group without exposure and gamma radiation (500 male, 501 female rats). All the animals were monitored until their natural death.

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 19 hours/day from the 12th day of pregnancy until death
ばく露2: 50 Hz
ばく露時間: continuous for 19 hours/day from the 12th day of pregnancy until death

General information

gamma radiation was applied once at an age of 6 weeks (about 0.21 Gy/min, total of 0.1 Gy); exposure was divided into two equal irradiations, performed on the ventral and dorsal side of the animals, respectively; in this way the rats were treated by two opposite irradiation fields, with an almost homogeneous dose distribution

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 continuous for 19 hours/day from the 12th day of pregnancy until death
ばく露装置
ばく露の発生源/構造
チャンバの詳細 polycarbonate cages (41 x 25 x 15 (remark EMF-Portal: cm?)) with covers made of non-magnetic material and a shallow layer of white wood shaving as bedding; cages were placed in exposure system in a room of 60 x 15 x 4 m3
ばく露装置の詳細 toroid was designed with 24 coils made of three turns of insulated copper cable, mounted on a superstructure of aluminum composed of two insulated parts; mounted inside the toroidal magnet was a wooden support structure for rat cages (5 rats per cage); the field lines were horizontal and parallel to the ground; the field uniformity was better than ± 10%; temperature was 22°C ± 3°C (remark EMF-Portal: or 22°C ± 2°C - contradictory specifications)
Additional information the exposure system was based on independent devices, each serving at least 500 rats; control group stayed in the same room as exposure groups; no noise and vibration were present during exposure
パラメータ
測定量 種別 Method Mass 備考
磁束密度 20 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 continuous for 19 hours/day from the 12th day of pregnancy until death
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 1,000 µT - 測定値 - -

Reference articles

  • Montanari I (2003): [50 Hz磁界の影響に関する大規模イン・ビボ実験のためのシステムの最適設計]

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 significantly increased occurence of mammary adenocarcinomas was found in males of group 1 (20 µT + gamma radiation) and in females of group 2 (1000 µT + gamma radiation) compared to the control group. In both groups, the number of animals bearing atypical precursor cells was significantly increased in males in females compared to the control group.
In males of groups 1 and 2, a significantly increased occurence of malignant schwannomas of the heart, and in males of group 2 a significantly increased occurence of lymphomas/leukemias in comparison to the control group was found.
No differences were found in body weight and survial between the exposure groups and the control group.
The authors conclude that exposure of rats to a 50 Hz magnetic field might have cancer promoting effects.

研究の種別:

研究助成

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