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

[SD雄ラットでの発がん作用誘発における50Hz正弦波磁界とホルムアルデヒドとの相乗作用] med./bio.

Synergism between sinusoidal-50 Hz magnetic field and formaldehyde in triggering carcinogenic effects in male Sprague-Dawley rats

掲載誌: Am J Ind Med 2016; 59 (7): 509-521

この研究は、雄および雌のSDラットを用い、50Hz正弦波磁界(S-50 Hz MF)とホルムアルデヒドの同時ばく露の相乗的発がん作用可能性を評価した。一つのグループは出生前から自然死までの全期間S-50Hz MFばく露を受け、かつ6週齢から104週間にわたり飲料水を介してホルムアルデヒドを摂取した。他の2つのグループはMFまたはホルムアルデヒドのいずれか1つのばく露を受け、もう一つのグループは無処置対照とした。その結果、共ばく露の雄ラットにおいて、対照に比べ、悪性腫瘍甲状腺C細胞がん血液リンパ細網系新生物発生率が有意に上昇した;雌ラットでは有意差が観察されなかった、と報告している。

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研究目的(著者による)

The carcinogenic effects of life-span co-exposure of rats to a 50 Hz magnetic field and formaldehyde should be investigated.

詳細情報

The present study is part of a large EMF animal test project, which has already been described in Soffritti et al. 2010.
In previous research, the authors found a slight, non-significantly increased incidence of cancer in rats exposed to 50 mg/l formaldehyde. This concentration was also used in this study, administered from 6 to 104 weeks of age via the drinking water.
Rats were divided into the following groups: 1) exposure to a magnetic field (253 males, 270 females), 2) co-exposure to a magnetic field and formaldehyde (200 males, 203 females), 3) exposure to formaldehyde (200 males, 202 females), 4) unexposed control group (500 males, 501 females). All the animals were exposed and observed until 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 from 6 weeks of age until death (max. 104 weeks)

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 from 6 weeks of age until death (max. 104 weeks)
ばく露装置
ばく露の発生源/構造
チャンバの詳細 rats in cages were placed in a large room with a temperature of 22°C ± 3°C and a relative humidity of 40-60%
ばく露装置の詳細 the field lines were horizontal and parallel to the ground; the field uniformity was better than 10%; there was no noise or vibration from current generator and coils; a maximum variation of 2°C was tolerated near coils; the 24 coils had a toroidal shape and were made of three turns of an insulated copper cable, mounted on a superstructure of aluminum composed of two insulated parts in order to avoid a closed loop subject to total field; the total copper cross-section was 11 mm x 28 mm; mounted inside the toroidal magnet was a wooden support structure for rat cages; each toroidal device was designed for the allocation of 500 rats, 5 per cage, distributed on five levels; the toroidal device had an external diameter of 4.7 m and was 2.1 m high
Additional information control animals stayed in the same room as the exposed animals
パラメータ
測定量 種別 Method Mass 備考
磁束密度 1 mT - - - -

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 incidence of malignant tumors, thyroid C-cell carcinomas and lymphomas/leukemias was observed in male rats co-exposed to the magnetic field and formaldehyde (group 2) compared to rats only exposed to the magnetic field (group 1) or the control group (group 4). No statistically significant differences were observed between males of group 2 and group 3 (formaldehyde only) and between female animals of all groups.
The authors conclude that there might be a synergy between life-span exposure of rats to a 50 Hz magnetic field and formaldehyde in terms of carcinogenicity.

研究の種別:

研究助成

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